CV44 TUNING

[Sonny S.]

What is your bike & build and what are the carb specs ?  CV44 ONLY
Do you have AFR data or a dyno sheet ?  If not, that's fine.

Thanks,
Sonny

[mayor]

Build details:
2002 FXD
'06 WFOLarry ported TC heads, stock valves and springs (and quench grooves)
95" SE flat tops
82cc head chamber and .030" cometic head gasket
Andrews TW37b cams
44CV carb
Zippers filter upgrade on SE backplate
SE6200 -5 degree performance ignition
Cycle Shack slip-ons on factory head pipe

WOT AFR running a 46 pilot (3 turns out), 195 main, DJ spring supplied by Larry and N8EL lean needle:


The cruise was around 14.8-15 afr and the idle was around 18:1.   I changed the jets to 48 pilot (1 1/2 turns) and 200 main.  I also pulled the spring that Larry provided out and replaced with the stock one.  Wide open the bike seems to run better, but at cruise it doesn't seem as smooth as the previous set up.  I since changed the spring back to the one Larry provided.  I  made another dyno run a couple of months latter with the new set up.  WOT AFR running a 48 pilot (1 1/2 turns out), 200 main, DJ spring supplied by Larry and N8EL lean needle:


I've tweeked the set up a little since the last dyno run.  I'm now running a N8EM ("M") needle and the A/F screw is turned about 2 1/2 turns out.  I didn't have any mechanical issue with the "L" needle, but the sound of the engine just wasn't quite right.  I lost about 1-2mpg, but I'm still in the 44-45mpg range.  My elevation is about 1,100 and I've riden from sea level to about 3,300 ft with no real issues.

[mayor]

Build details:
2002 FXDL
'06 WFOLarry ported TC heads, 1.9" valves and stock springs (and quench grooves)
95" SE flat tops
80cc head chamber and .030" cometic head gasket
Andrews TW54 cams
44CV carb
SE filter on SE backplate
SE Adjustable ignition (curve 2, advance 0, Rev 6k
Cycle Shack 2 into 2 M-pipes

CV44 carb particulars are:
48 pilot (about 3 turns out), M needle and 210 main. 



cruise was around 14.4-14.6:1


I decided to play with the jets, needle and slide spring, so here's what the build's afr looked like with a 50 pilot (1 1/2 out), L needle and 220 main:

[Sonny S.]

Well Mayor,

Looks like carb's are starting to be a thing of the past.
Even our dear friend Max has crossed to the other side   

[Lovetoride007]

Just built a axtell 107 on a 04 flhtc, Dewey heads w/ grooves,9.8to1, HQ 575 cams, super trap 2-1, CV44 w/ 50 pilot 2 1/2 turns out,Woods KT3 needle and 220 main , running DTT wego 2 AFR meter have 300 miles on it ,AFR #s are in 35-40 DEG weather,my idle is about 13 to 1  cruise is about 14.5 to 15 and on a couple of roll ons it was about 14.5 , will have better info when broke in. Got 32 mpg first tank

[Sonny S.]

LTR,

Great info.  Thanks !

[Sonny S.]

FROM : Fxstchewy in another thread

I switch out from time to time on my Hippo motored FXST, I use a HSR 42 and CV44, the 44 works great and the bike starts better with the CV, jetting is 50pj approx 1.5 turns out, "L" needle and the stock 220mj, the HSR 42 seems to have a little better response but overall they are very close. Chewy

[mayor]

>Do you have AFR data<

Yes, it was a CV44, 95" T/C .57" lift cam

Right or wrong that's how I jetted it.

maybe I'm missing something, but I didn't see the jets you used to achieve the posted numbers.  Can you be more specific? 

[mayor]

Maybe I don't understand the question, are you asking for specific CV 44 jetting used for specific builds regardless if the jetting is correct? 

I think what Sonny was asking for is simply data-  jets and afr in relation to build, and after that caveat emptor.     I think I read on the internet that not everyone follows the guidelines you laid out for the AFR, so just data is best- that way we can make our own informed decision based from the data.   

[FLTRI]

>Do you have AFR data<

Yes, it was a CV44, 95" T/C .57" lift cam

Idle 12.25 - 13.5
WOT 12.25 - 13.2 (cold) 12.7-13.5 (hot)
Cruise 13.2 - 14.5
Decel 17.1 (Minimum)

Right or wrong that's how I jetted it.

IMO, this is just about as good as it gets, regardless of what anyone has read, these AFR numbers are excellent targets for any build. With a carb it is all about compromise and these ranges are very much within expected results from proper tuning. Very well done PHR.
As always, JMHO, Bob

[Sonny S.]

Bob,  you just created a monster..lol

I already KNOW what target AFR ranges are. Besides, cruise 13.2 -14.5 ...really ?   
That wasn't what this thread was about.
That post is like telling someone you ran 9.1:1 dynamic compression, and made 100 - 110 HP but not listing the combination of parts used. BFD

Bob, don't you use a starter map that you have created from a previous tune or do you just start from scratch every time ?

[FLTRI]

Sonny:
Sorry if I offended anyone. LOL!
"Besides, cruise 13.2 -14.5 ...really?" Answer:

Code Select Expand

Yessir!
As RPH correctly stated:
"It seems that as the throttle moves so does the air and the fuel."
This lack of consistency is common with carbed bikes, exacerbated with high overlap cams and open 2into2 exhaust systems. Another reason EFI is superior the carbs.

"don't you use a starter map that you have created from a previous tune or do you just start from scratch every time?"
This thread is concerning a CV carb, not sure what analogy you are using here, but to answer your question:
I always try to find a good base map for any tuning method where no changes can be made with the engine running (SEST, TTS, DirLink, etc), however I have no problem starting from scratch with a PowerCommander due to the luxury of tuning while the engine is running and I'm reading AFR changes live.

[Sonny S.]

" This thread is concerning a CV carb, not sure what analogy you are using here, but to answer your question:
I always try to find a good base map "

Yes, and I was asking for the same thing but instead of a base map.... jetting.
That's all...nothing more. Builds with CV44 carbs, how they were set up and ACTUALL AFR results.
Not AFR ranges, not what is best, not what does anyone think, not what someone heard at the water cooler one day.
Not even how a CV40 or 51 was set up on whatever.

I understand what you are saying about if the throttle moves while cruising..got it.
However, I've asked you in the past about a target AFR on my own carbed bike and you NEVER gave such wide ranges.

Bob I value your suggestions and pay attention to what you say.
Here are just a few posts from you about AFR, and I don't see you saying 12.25 idle. 12.25 WOT or 13.2 cruise.
IMHO these numbers are totally unacceptable for a street bike...carbed or not.


If you set your cruise AFR to 14.2-1 you will find the performance is good and the mpg is outstanding. Just adjust the cruise range for this AFR and the rest at 13.5 and you will be fine.
Only for racing engines used for racing do we tune any richer that 13.5 AFR.
As always, JMHO, Bob

mtm,
"Or do you just chop them from 13.5 to 14.2 and back again?"
Exactly, or if you wish you could taper the AFR in and out but the most important point is to make sure you are operating in the 14.2 during cruise, your cruise/speed.
Don't over think this and don't worry if your engine ends up running at 14.2 most of the time, even under substantial loads. Remember the stock engine is tuned to 14.6-15.2 most of the time.
There is way too much concern that 14.0-14.2 is lean and will harm engines. Quite to the contrary IMO running too rich does more damage over time, not to mention the absolute waste of fuel and dirty air to boot.
Anyway off my soapbox, sorry for the run-on, and as always JMHO, Bob

Vic,
From my POV, there is really no reason for AFR to be any richer than 14.0 @ idle. There is absolutely no load, and no rpms to create heat.
I find bikes tuned to 14.0-14.2 @ idle as well as all light loads/lower rpm run very well and get great mileage.
I know there are those who say they set their idle to 12.8-13.2 to cool their engine, but I believe there must be something else causing the heat if it has to be that rich @ idle.
Hope this helps, Bob

[FLTRI]

OK sonny,
I think I see where the confusion lies. With EFI we can get the AFR perfect everywhere, however with a carb there is always fluctuation in what the AFR does @ different rpms/tp. I try for best compromise to the target but sometimes the build/exhaust will only allow a mean average, with up to 1.5-2 AFR from leanest to richest readings. This applies to part throttle as well as WOT.

I find Mikunis are the best for holding AFT to target and the CV next, followed by S&S carbs.

I always start with whatever the carb comes with and work from there. Most of the time folks try to second guess what the jetting "should" be just to find out the stock jetting was closer than the guess. This is especially true with Mikunis and CVs. S&S carbs usually come with too big a main jet.
Hope this helps,
Bob

[Sonny S.]

I always start with whatever the carb comes with and work from there. Most of the time folks try to second guess what the jetting "should" be just to find out the stock jetting was closer than the guess. This is especially true with Mikunis and CVs. S&S carbs usually come with too big a main jet.
Hope this helps,
Bob

Bob,
I really hate even keep this going but....

I'm no tuner but I'm also not a dumbass. I know EFI is different and more accurate.
I'm not sure why my WEGO III or my CV40 would hold steady a perfect # at WOT but it does. That is of coarse after an initial rich dip when the throttle is cracked. Limiting accelerator pump squirt of course lessens that.
Even at cruise and idle when the bike was warmed up the #'s would NEVER vary .5, unless of coarse road conditions, throttle position, wind, a passing vehicle, a low flying duck..etc.
If you want to blame the WEGO, well, Iv'e seen others post the same results with an LM-1 and other AFR " meters " not LED gauges. PHR is using a RSR gauge that only shows colored lights for AFR #'s and nothing specific other than I believe 17.1,13.2,12.2....something like that. Either way, you could not read a true 13.5:1 if you wanted to.I know, those are the only numbers that matter so it is perfect 
Yes it will keep you in the " safe " range

Now for starter jetting. You're going to tell me that if you installed a street legal CV44 on a motor that from your previous experience would require more fuel, that you would still start with stock needle / jet ?  WHY ?
If you knew for a fact that the leanest needle available was in that carb, you would run it anyway, knowing you would have to swap needles, even if it meant pulling the carb ?  WHY ? ......
or would you say....hmmm , the last few times I've tuned a CV44 on a motor like this, the " L " " M " ( whatever ) needle is what I used so I think I'll just start with that ?

Look, I know you don't even like carbs, so I find it hard to believe that you're going to dick around with one any longer than you have to.


Edit :

I forgot to mention the 12.25-13.5 idle that you agreed with PHR on. IMHO 13.5 yes.
I realize that EFI and carbs are different but don't the same idle AFR's apply but what about this statement.
From my POV, there is really no reason for AFR to be any richer than 14.0 @ idle. There is absolutely no load, and no rpms to create heat.
I find bikes tuned to 14.0-14.2 @ idle as well as all light loads/lower rpm run very well and get great mileage.
I know there are those who say they set their idle to 12.8-13.2 to cool their engine, but I believe there must be something else causing the heat if it has to be that rich @ idle.
Hope this helps, Bob


Also, PHR,  how are you getting 17.1 decel with the CV ? Are you blocking off the decel enrichener ?

[FLTRI]

Sonny,
I guess I should have qualified my statements by saying if it is a repetitive build that I know based on history requires different jetting, yes I will make changes prior to tuning.

Also, since the CV40 is a smog carb there are known low speed and needle changes that are well documented, but that only applies to the EPA carbs, not aftermarket, performance carbs such as Mikuni, S&S, CV44, CV51, Edelbrock, PSI, etc. These carbs come with jetting based not on EPA, but on mfg testing and development, so prejetting may not even be in the right direction.

A little suspect that your AFR "NEVER" varies more the .5 afr, unless you are referring to static rpm/tp, or have a stock cam and good back-pressure exhaust. Usually with high overlap cams, 2into2 exhaust, goofy air cleaners, etc, will affect the way the engine breathes varying AFR readings. Unlike EFI with well over a 100 rpm/tp cells for each cylinder, there are only at most, 3 normally adjustable circuits in a carb that feeds both cylinders.

PS- It's not that I don't like carbs, it's that they are such a compromise compared to EFI, I can't make the tune perfect for all rpm/tp. Hard to be perfectionist with carb tuning, even after spending 3-4 hrs modifying circuits, adjusting float levels, changing jets, modifying air bleeds, changing CV slides and springs, adding/jetting Thunderjets, and adjusting accellerator pump output.

HTH,
Bob

[Sonny S.]

A little suspect that your AFR "NEVER" varies more the .5 afr, unless you are referring to static rpm/tp, or have a stock cam and good back-pressure exhaust. Usually with high overlap cams, 2into2 exhaust, goofy air cleaners, etc, will affect the way the engine breathes varying AFR readings.

The one I was refering to was..
95"
06 Heads
TW37's @ 9.5
SuperMeg 20 discs closed cap
Zippers filter with SE backing plate

I was testing on a nice flat road it was very consistant. I looked at a data log and did see spots where is would very more than others but there are several places where it stayed .4-.7. So, NEVER should have been left out 

Look's like we are winding down to a nice place to put this conversation to rest    

[FLTRI]

Sorry I got involved. Didn't realize it was pissing match. I thought there was a bit of good info for someone with a CV44 that wanted to know how they react and what was usable jetting, and how to compromise.
Let's play nice, boys

[Fxstchewy]

Leave the thread........I can read thru the bs... good info on the CV44, Thank's for all who put in their .02 

[Sonny S.]

Chewy,

I went through and just deleted a bunch of the totally unnecessary BS that you had to read through...well, all I could anyway 

[mayor]

well 'ol Red finally bolted on a CV44 carb to his RK, now he has actual data to contribute ( ).  He sent me his run files, so I figure I'll update this thread with some more data points.  Here's his afr:

Build details:
2000 RK
95"
9.3:1 (180 ccp)
Crane 300 (gear)
D&D Fat Cat (quiet baffle)
SE CV 44 (50 pilot /M- needle /200 main)
Syke Performance Ported Heads (1.9"/1.61")
Stk ignition
SE Stage I A/C

I believe he told me his cruise afr checked out to be around 14.1-14.4. 

[FLTRI]

Hmmmm. Wonder why the AFR isn't very straight?
Does the torque graph have a corresponding dip to the AFR?
Bob

[mayor]

yep there's a tq dip, but not so much of one.  More like a "tell-tail" sign of a fatcat. My guess is any other pipe, and more of a dip would be present in the tq curve. here's his chart:
http://www.harleytechtalk.com/htt/index.php/topic,17237.0.html


looks like all three afr charts I posted of the CV44 has an over active accelerator pump.   

[Sonny S.]

yep there's a tq dip, but not so much of one.  More like a "tell-tail" sign of a fatcat. My guess is any other pipe, and more of a dip would be present in the tq curve. here's his chart:
http://www.harleytechtalk.com/htt/index.php/topic,17237.0.html


looks like all three afr charts I posted of the CV44 has an over active accelerator pump.   

really ?
whatcha thinking ?
something wrong with the carb ?

[mayor]

really ?
whatcha thinking ?
something wrong with the carb ?

 

just saying.   

[Sonny S.]

________________________________

just sayin   

[Jeffd]

so would shortening the rod on the acc pump help?

[Sonny S.]

that would delay the squirt as well as decrease it....could help

[FLTRI]

How 'bout a reason the AFR graph has such a wide variance in AFR: From about 11.7:1@2200rpm, up to 14.2:1@2700rpm, down to 12.5:1@3200rpm, and back up to 13.8:1@4500-up?
What can cause this swing in AFR?
Hint #1: It is not the accelerator pump.....except for a maybe a bit of richness @ 2200rpm, but the pump's influence is gone after about 1 second, or less, into the run so the rest of the AFR graph is devoid of influence from the accelerator pump.
Hint #2: It may be more than one issue causing the variance.
Disclaimer: This is assuming there are no issues/problems with the basics like AFR pumps not serviced properly, no air leaks in the exhaust system, or anything else that can corrupt the AFR readings.
Bob

[Don D]

BTW if you try to tune the Accel pump you can change the bypass hole as well for additional fine tuning

[mayor]

well I'll take a stab at Bob's questions:

How 'bout a reason the AFR graph has such a wide variance in AFR:

From about 11.7:1@2200rpm- pilot possibly set too rich, since this would be the split second the throttle was wacked before full load was registered

up to 14.2:1@2700rpm- load was applied and main jet was called to duty, but the acc pump gas had been sucked into the chamber yet

down to 12.5:1@3200rpm- accelerator pump squirted compensating for rapid gas need (although, over compensated is my official answer)

..and back up to 13.8:1@4500-up?- main jet was the source for gas needs.

What can cause this swing in AFR?
Hint #1: It is not the accelerator pump.....except for a maybe a bit of richness @ 2200rpm, but the pump's influence is gone after about 1 second, or less, into the run so the rest of the AFR graph is devoid of influence from the accelerator pump.
Hint #2: It may be more than one issue causing the variance.
Disclaimer: This is assuming there are no issues/problems with the basics like AFR pumps not serviced properly, no air leaks in the exhaust system, or anything else that can corrupt the AFR readings.
Bob

here would be my list of possible answers:

1. exhaust reversion (pipes or valves)
2. cam over lap (I/E)
3. cam timing (cylinder fill/cylinder empty issues)
4. exhaust pipe system compatibility
5. ignition timing
6. cylinder head flow velocity
7. constraints to fresh air (ac)
8. emulsion tube design
9. not enough tuning circuits in the CV44 carb
10. afr sampling rate
11. afr calibration
12. afr gremlins
13. AMC Gremlin


or combinations there of...

.....but in reality, a carburetor is a great compromise in supply of gas to an engine.   


how'd I do?

[FLTRI]

well I'll take a stab at Bob's questions:

How 'bout a reason the AFR graph has such a wide variance in AFR:

From about 11.7:1@2200rpm- pilot possibly set too rich, since this would be the split second the throttle was wacked before full load was registered

Pilot jet will not affect WOT...even for a split second.

up to 14.2:1@2700rpm- load was applied and main jet was called to duty, but the acc pump gas had been sucked into the chamber yet

Definitely the main jet was called to duty, but lack of velocity would be my guess as to the lean reading.

down to 12.5:1@3200rpm- accelerator pump squirted compensating for rapid gas need (although, over compensated is my official answer)

The accelerator pump was finished well before the rpms got to 3200.

..and back up to 13.8:1@4500-up?- main jet was the source for gas needs.

Fuel @ 4500-up is controlled by the main jet. Note: Usually the front and rear cylinder run different AFRs so it depends what cylinder the reading was taken. Ie: if the front cylinder was what produced the reading the rear cylinder could be leaner or richer than the front cylinder. Based on the this the main jet could be as good a compromise as possible or the "other" cylinder may be too lean or on the richer-than-necessary side.
This is why we always sample both cylinders on carbed bikes. This way we know where the jetting compromise needs to be.

here would be my list of possible answers:

1. exhaust reversion (pipes or valves) - BINGO!
2. cam over lap (I/E) - BINGO!
3. cam timing (cylinder fill/cylinder empty issues) YEP!
4. exhaust pipe system compatibility - YOU BETCHA!
5. ignition timing - Not so much
6. cylinder head flow velocity - ALSO POSSIBLE!
7. constraints to fresh air (ac) - Huh?
8. emulsion tube design - Possible, but not as likely
9. not enough tuning circuits in the CV44 carb - Also possible but not likely
10. afr sampling rate - Not unless there is a problem with the system
11. afr calibration - Probably not
or combinations there of...
.....but in reality, a carburetor is a great compromise in supply of gas to an engine. - TRUE!
how'd I do? [/quote]
You done good Mayor.  
Basically the exhaust system design and/or cam profile is what will shape the fuel curve. The rest of the variables can and do influence the curve but exhaust/cam that makes up most of the curve's personality.
Bob

[Jeffd]

so acc pump not much of an impact but how about the slide going up too fast due to too light of spring or too big of vaccum hole.  too much air pulling too much fuel?  ok I will go sit down and shut up know..

[FLTRI]

so acc pump not much of an impact but how about the slide going up too fast due to too light of spring or too big of vaccum hole.  too much air pulling too much fuel?  ok I will go sit down and shut up know..

If the slide is pulled too soon it will go a bit lean, then the velocity picks up and draws more fuel. So there can be a bit of confusion for the slide if the vacuum hole is too big.
For the most part if the vacuum hole hasn't been "hogged out" or the spring changed to too light tension, the velocity stays relatively high as the slide moves up and consequently draws more fuel through the main jet keeping the fuel/air balance on target.
It is only from screwing up that balance does the AFR get messed with.
The proof of that is readily seen with a bone stock bike. The AFR will be very flat. Then open up the hole in the slide too much and/or lessen the spring tension (Dynojet type kits) and the AFR curve no longer stays flat.
As always, JMHO,
Bob

[mayor]

The accelerator pump was finished well before the rpms got to 3200.

I'm not sure I completely buy that.  Take a look at the following afr example:


The Red, Green, and Blue lines are from different bikes using different cams and different exhausts configurations, and the only thing in common they have is they are equipped with the CV44 carb.  

Blue is from a TW54 ported heads (1.9"v) build using CS M-pipes 210main

Green is from a Crane300 ported heads(1.9"v) build using a D&D 2 into1 200main

Red is from a TW37 ported heads (1.805"V) build using factory head pipes and CS mufflers 200main

So, you saying that dip isn't related to the accelerator pump?

[Admiral Akbar]

So, you saying that dip isn't related to the accelerator pump?

It's not.. You need to drill an 0.040 hole at the top of the emulsion tube above the other holes.  Max

[FLTRI]

Gotta say Mayor I'm a bit perplexed. I know I shouldn't be because I see what cam profiles, accelerator pumps, exhaust systems, ports, big valves, small valves, exhaust systems of every design, do to fuel curves.
Here we have completely different builds, including cam profiles, porting, and different exhaust designs.....same fuel curve profile???
Got me

[mayor]

yea Bob, one more example of why efi is friendlier to tq curves.    

I like where Max is going with the emulsion tube holes, but I see that as a crap shoot on size and qty since it may require testing for each change to measure results. 

hey Max, rev limit on my tw37 build is set to 6.2k........take a gander at where the afr shuts off at.     se6.2 ignition, so could be noise or a problem created by one of those E.E. types.  I've got run files from 2 separate runs on that bike (3 pulls each), and each one carries the dropping tq line past 6.5k.  Another interesting note- the tw54 build stops at 5.8k (SE adjustable ignition set at 6k).

[Admiral Akbar]

so could be noise or a problem created by one of those E.E. types

Nope, Probably some idiot SW type... Max

[FLTRI]

yea Bob, one more example of why efi is friendlier to tq curves.

But we are talking about fuel curves not torque curves.
Try looking at those runs based on time in lieu of rpm.
Look at how the fuel curve goes as time passes. You should see the accelerator pump would have to go for a lot longer period of time to make the AFR go rich, that rich, for that long.
IME the way an engine breathes (cams, heads, intake, exhaust) dictates the fuel curve profile....not the carburetor...BWTFDIK
Bob

[Don D]

Wouldn't an AFR trace line flat as a pancake be fake on a carb bike?

[Sonny S.]

Jeffd has a flat AFR line with a CV .....don't know why but he does 

[mayor]

yea Bob, one more example of why efi is friendlier to tq curves.

But we are talking about fuel curves not torque curves.

...sorry, I was withholding evidence.  The tq curves follow the dips in afr on all three of those builds.   

it's funny, a fellow would think that the dips in afr would cause peaks in tq since 'ol Red is convinced that more gas is more power.  sorry couldn't resist busting on Red on a debate that's lasted almost two years.....although I think we might have him convinced otherwise now, since his recent afr was more towards our way of thinking

here's an afr/time comparison:

eventhough there's two Mississippi's between where the dip starts and ends, I can still see how the acc pump could be at the very least part of the problem.  The carb is working on vacuum, so if the vacuum momentum falls I can see how the affects could lag?  bwtfdik.    I agree that ususally the combination of components is what causes the afr signature in a carb build, but the signature is the same on the three vastly different builds that I posted the afr comparison for....so the one common denominator (cv44) probably bares some responsibility.  The more I think about it, I'm leaning towards the emulsion tube as Max mentioned. 

[Sonny S.]

>>>The more I think about it, I'm leaning towards the emulsion tube as Max mentioned<<<

why ?
then what ?
go ahead and drill it....lemmee know how it goes.

doesn't reds bike rev raster than both of yours?
and the 54 build revs faster than the 37 ?

[Admiral Akbar]

Hey Mayor, Thanks for the pic.. Max

[mayor]

doesn't reds bike rev raster than both of yours?
and the 54 build revs faster than the 37 ?

well, I'm not real sure how accurate the time function on the run files will show that, since some of that is subject to the fellow twisting the wick....but here's proof that my fxd can rev as fast to 5252 as red's roadcow:


I had to hunt for that run though, all three pulls of the lowrider seemed to reach that point over a half second slower. 


as for the other questions you asked......blame it on being a fellow who just has to tweak.     I won't drill the stock one, I'll order a back up first. 



no problem Max.....I have a feeling I may have given Red one of you as well.   

[FLTRI]

on a debate that's lasted almost two years.....although I think we might have him convinced otherwise now, since his recent afr was more towards our way of thinking

here's an afr/time comparison:

eventhough there's two Mississippi's between where the dip starts and ends...

So the throttle was opened and about a 1/2 sec later the AFR went a bit lean (>14.0). Speed of the thottle opening can affect this picture.
After 1 full second the pump's fuel just got to the combustion chamber and continued to squirt fuel into the carb throat for a couple Mississippi's???

Next time you have your a/f off check how long the accellerator pump squirts fuel into the carb.
Now imagine velocity helping to move the additional fuel through the process.
Do you still feel the pump is the culprit?
I think the carb can be tuned to help but not eliminate the basic builds breathing which dictates how and when the fuel is drawn through the carb.
As always, JMHO, Bob

[wfolarry]

Reminds me of the S&S dip that putting in an adjustable air bleed helps smooth out. S&S now puts them in from the factory so you can tune it.

[mayor]

After 1 full second the pump's fuel just got to the combustion chamber and continued to squirt fuel into the carb throat for a couple Mississippi's???

Next time you have your a/f off check how long the accellerator pump squirts fuel into the carb.
Now imagine velocity helping to move the additional fuel through the process.
Do you still feel the pump is the culprit?

well..  probably not so much....   I just need to practice how fast I can say Mississippi......

[PanHeadRed]

Mayor for what it's worth, here is the TQ curve and the AFR from my engine with the CV40 250 main and Caliber 2-1.

It could be drowning.

[attachment removed after 60 days by system]

[Admiral Akbar]

Where did you find a 250 main? or did you just use an 1/8 inch drill?    Max

[mayor]

Sorry Red, but I don't believe for a minute that the data you are presenting is "real".      furthermore, I seriously doubt that a 250main in a cv40 would show almost the same afr as a 200 main in a cv44 with the only change being the exhaust from a Caliber to a D&D.  is that to imply that the Caliber pulls more air than a D&D (despite all the evidence of the effectiveness of the D&D)? or would you be suggesting that the main acts differently in a cv44 than it does in a cv40?  my guess is there was either an error in what was recorded, or what was posted.....

[Admiral Akbar]

Sorry Red, but I don't believe for a minute that the data you are presenting is "real".      furthermore, I seriously doubt that a 250main in a cv40 would show almost the same afr as a 200 main in a cv44 with the only change being the exhaust from a Caliber to a D&D.  is that to imply that the Caliber pulls more air than a D&D (despite all the evidence of the effectiveness of the D&D)? or would you be suggesting that the main acts differently in a cv44 than it does in a cv40?  my guess is there was either an error in what was recorded, or what was posted.....

Ya know it is totally possible that Red is runnin' a 250 without problems..

Max

[mayor]

Ya know it is totally possible that Red is runnin' a 250 without problems..

in a 95" with a CV40....netting 13.5:1 afr?  sorry just not buying it.....

[FLTRI]

Ya know it is totally possible that Red is runnin' a 250 without problems..

in a 95" with a CV40....netting 13.5:1 afr?  sorry just not buying it.....

I personally have not seen where a 250 main could effectively (not grossly rich) be used in a CV40 for any build.
Normally a typical 185-195 main will provide 13.0-13.5 AFR @ WOT.
A 250 should run the AFR down to about 11.0-11.5:1 which is way too rich to make power....on gasoline.
Maybe we're talking a special gas/alky blend?
Just my $.02,
Bob

[PanHeadRed]

>Sorry Red, but I don't believe for a minute that the data you are presenting is "real".<

It's posted on HTT how could it possibly not be true?

[PanHeadRed]

Max, there was problems, if I left the enricher out to long it would kill the plugs.

Mayor, believe what you want, but that run was recorded on the Dynojet 250 what ever at Fast Lane Cycles in Chantilly Virginia with a 250 main in my CV40. The tuners name was Will, the shop was a Sport Bike shop, what I remember most about the day (other then breaking a pair of sun glasses) was the tuner got on the phone and called the owner of Devil Dog Cycles and said "you got to come over here and see this".

Fucked up sniffer? Don't know, don't care. 

I don't think Will buys that less fuel less timing thing either.

I you wish I will mail you the jet and you can measure it for your self. Maybe it's a 249.9 and not a true 250.

[PanHeadRed]

Here are the AFR's from 24 runs that day, some are 3rd gear, some 4th some 5th. They go from 200/shims to 250


[attachment removed after 60 days by system]

[FLTRI]

"potty mouth! "ed up sniffer? Don't know, don't care. 

PHR,
I would think you should care if the AFR readings are correct. The way the tuner evaluates the AFR/power is by the signal from the O2 pump/sniffer.

If this data is not right (reads lean from air getting into the OG sensing system) the tuner will make changes to get the readings to look correct.
Service a missreading pump (eliminate air entry) and the AFR rich goes rich because it no longer gets outside air into the sensing system.

Anyway the need for a 250 main in a CV40 to get AFR to 13.0-13.5 on a 95" build with your exhaust, cams, and intake just doesn't make sense.

If I were the tuner and needed to check the validity for using the 250 main, I would simply install what I had been using for those builds (185-195) and do a pull to see what the power did.
If power went up, I would know the AFR readings were bogus. If power went down I would have to accept the 250 was prolly the correct jet.
Heck, you may have a bit more power/mileage left in that build.
Bob
PS - The fact that if the enrichener is left on too long it kills the spark plugs is a good indicator the AFR is too rich without the enrichener. Remember the enrichener also adds air not just fuel, so a properly tuned engine should be able to run just fine with the enrichener out, albeit a bit rich @ low rpms, without fouling plugs. Also, you should not need the enrichener to cold start your engine?

[PanHeadRed]

>PHR,
I would think you should care if the AFR readings are correct.<

Bob, my "don't care" statement is not as it reads, I'll explain later. That carb tune was done a few years ago, I rode that bike to NOLA and back, at times on reg gas the 3rd week in July, no problems. But I took the 250 out at the end of that summer, I prefer the tune I get using my AFR meter.

That guy tuned it I rode it, it ran fine (cept for the plug thing) I also ran it for a long time with a 220 and one shim.

I used a 200 with 2 shims, a 220 with 1 shim and a 250 with no shims, they all graphed fine depending on who's graph and what an individual wants to classify or accept as an acceptable AFR.

[mayor]

my guess is the "don't care" was directed towards another fellow.     

[FLTRI]

Red,
What color are your plugs? They should be a shade off white (we no longer have leaded gas so the tan color is no longer good).
If you were to use a high powered light like the doctor uses to look in your ears, you should find a very small ring of color at the very base of the porcelain.
If you show color on the rest of the porcelain then it is rich.

As I have mentioned, unless the air bleeds have been "bored out" a 175-195 would be really close.

The fact you are using CV44-size jets in a smaller carb tends to indicate way more fuel than necessary.
Also the enrichener deal points to too rich as well.

Just for grins maybe slide a 180 main and go for a ride and see if it doesn't feel perkier and less apt to foul plugs.
Just my $.02,
Bob

[PanHeadRed]

>my guess is the "don't care" was directed towards another fellow.<     

Not at all, I was just pointing out that it was so long ago it no longer matters..........to me.

My point was here is a chart that shows a 250 slightly rich, and I can show another that shows a 200 shimmed even richer. Which sniffer is right which is wrong? Maybe there is error in both?

[PanHeadRed]

>The fact you are using CV44-size jets in a smaller carb tends to indicate way more fuel than necessary.
Also the enrichener deal points to too rich as well.<


Bob, I was but am not currently. Current set up is a 44,  50 slow - M needle - 200 main

Current WOT is high 13's SS Cruise with a 30% load is middle 14's. I liked it the Dyno guy liked it, so I don't see a 185 in my future.

The 250 in the 40 was a few years ago. I went in for free Dyno time (a couple of pulls to measure power no tunning) with a 220 and one shim. The operator offered to tune it for "free" so I let him do his thing, I left with a 250 and no shims. Rich? Yeah with the cable pulled, Death to the engine? Not hardly.

But like I said that was a few years and exhaust systems ago, I have moved on.

[FLTRI]

>The fact you are using CV44-size jets in a smaller carb tends to indicate way more fuel than necessary.
Also the enrichener deal points to too rich as well.<
Bob, I was but am not currently. Current set up is a 44,  50 slow - M needle - 200 main

Those numbers look right for the application....more air - more fuel.
The CV40 with the 250 is less air - more fuel, too much fuel.
The tune was free and you got what you paid for IMO.
Anyway glad to hear you got it right in the end,
Bob

[Admiral Akbar]

My point was here is a chart that shows a 250 slightly rich, and I can show another that shows a 200 shimmed even richer. Which sniffer is right which is wrong? Maybe there is error in both?

Come on.  You guys don't know why that motor is going way rich at WOT with a 250 main?

Max

[FLTRI]

Come on.  You guys don't know why that motor is going way rich at WOT with a 250 main?
Max

U-h-h-h, because the main jet is too big???

[Admiral Akbar]

Come on.  You guys don't know why that motor is going way rich at WOT with a 250 main?
Max

U-h-h-h, because the main jet is too big???

ooops

Come on.  You guys don't know why that motor is not going way rich at WOT with a 250 main?

Max

[Jeffd]

I had a dyno run once by a guy who built some world record horse power hybusa motors (arcane motorsports) and he was not familar with v-twins and he stuck the sniffer barely in the end of the muffler and got a lean reading no matter how big of jet we put in.  I wonder if the dyno run with the 250 main was doing the same thing?  sniffer not far enough up the pipe.

[FLTRI]

I had a dyno run once by a guy who built some world record horse power hybusa motors (arcane motorsports) and he was not familar with v-twins and he stuck the sniffer barely in the end of the muffler and got a lean reading no matter how big of jet we put in.  I wonder if the dyno run with the 250 main was doing the same thing?  sniffer not far enough up the pipe.

Possible. All I'm saying is the AFR reading isn't correct if a 250 main in a CV40 shows anything but pig rich @ WOT.
Just my $.02,
Bob

[Sonny S.]

I had a dyno run once by a guy who built some world record horse power hybusa motors (arcane motorsports) and he was not familar with v-twins and he stuck the sniffer barely in the end of the muffler and got a lean reading no matter how big of jet we put in.  I wonder if the dyno run with the 250 main was doing the same thing?  sniffer not far enough up the pipe.

Possible. All I'm saying is the AFR reading isn't correct if a 250 main in a CV40 shows anything but pig rich @ WOT.
Just my $.02,
Bob

[Admiral Akbar]

I had a dyno run once by a guy who built some world record horse power hybusa motors (arcane motorsports) and he was not familar with v-twins and he stuck the sniffer barely in the end of the muffler and got a lean reading no matter how big of jet we put in.  I wonder if the dyno run with the 250 main was doing the same thing?  sniffer not far enough up the pipe.

Possible. All I'm saying is the AFR reading isn't correct if a 250 main in a CV40 shows anything but pig rich @ WOT.
Just my $.02,
Bob

  Sure it's possible to from 220 to 250 and not have the AFR read rich..  If you don't think so then you don't understand how the CV works.. Same for all slide type carbs..

Max

[Sonny S.]

95", mild compression, low lift, short duration cams. You think that motor can move enough air through it with a CV40 to support a 250 main ?

IMHO, if a 250 main is needed then HP #'s should be very high.

but then again, I don't understand how the CV works 

[Admiral Akbar]

You think that motor can move enough air through it with a CV40 to support a 250 main

It depends on the diameter of the needle at the end.. Heck you even be able to go bigger.    Max

[PanHeadRed]

>You guys don't know why that motor is going way rich at WOT with a 250 main?<

Nope I don't, it showed 12.7 - 12.2 on the meter. That may be to rich for some schools of thought, maybe not others.

Define rich.

[PanHeadRed]

>sniffer not far enough up the pipe.<

That's not the point, the point is I have a AFR print out from a Dyno run, and a guy from the internet backing it up. 

[PanHeadRed]

This ones better the bike was warmed up by #4 and he reved it to 5000.

This one will demonstrate that you do indeed make more TQ and HP (at least one) with less fuel.

#4 is 200 w/2 shims
#25 is 250 no shims.



Mayor was right.

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[FLTRI]

You think that motor can move enough air through it with a CV40 to support a 250 main

It depends on the diameter of the needle at the end.. Heck you even be able to go bigger.    Max

Max,
You are correct, if someone had some special fat needle it would take a bigger main to get the same results as from the normally used needle size and main for that application. That said, why would anyone opt for a fat needle over the normally used 2 needle sizes for that type build?

PHR,
IMO rich/too rich is defined when jetting gets to the point where adding more fuel to the mix loses power.
Bob

[Admiral Akbar]

Max,
You are correct, if someone had some special fat needle it would take a bigger main to get the same results as from the normally used needle size and main for that application. That said, why would anyone opt for a fat needle over the normally used 2 needle sizes for that type build?

Well a the needle for a stock carb should have the right (reasonably right smog or whatever) need to allow adjustment of the main.. On a stock bike this could be the case.. Start pulling a bunch more air through it, up the jetting and the end of the needle may appear too fat to supply enough fuel.. At that point the main does not adjust WOT but the needle does. Something to what out for.

Max

[FLTRI]

At that point the main does not adjust WOT but the needle does. Something to what out for.
Max

So no matter how big the main is the needle controls WOT fuel???
A fatter needle may need bigger main for proper WOT AFR but it doesn't change the fact the bigger the main the more fuel with a given needle size.
Bob

[Admiral Akbar]

Take 2 ends of  a pipe. Plug one end up.. Don't matter how big the other end is.. Max..

[FLTRI]

Take 2 ends of  a pipe. Plug one end up.. Don't matter how big the other end is.. Max..

Sorry, I didn't realize you were talking about a needle diameter that was the same inside diameter as the jet.
What application would that be used for???.. Bob

[Sonny S.]

Max,
stick a CV40 set up just like PHR's was on your FXDX and lets see what happens.
Carb shoot out 4 ......on the bike testing

I do agree that running a very lean needle will require a larger main in order to get cruise AFR in the ball park, however WOT would be rich. IIRC none of the stock TC needles are lean at the end.

[Admiral Akbar]

Glad to be back on US soil... 

Ok,
I feel a home work question coming on.. 

Which has more flow based on area.  A 250 main jet (assume 250 means 2.5 mm) or a  0.12 inch needle jet with a needle that is 0.071 inch diameter needle at the end when the slide is raised all the way.. Remember the inches to mm or mm to inches conversion.. 

Sorry, I didn't realize you were talking about a needle diameter that was the same inside diameter as the jet.

Well I was trying to make an extreme point.. Apparently it didn't work.. 

Max

[FLTRI]

Glad to be back on US soil... 

Ok,
I feel a home work question coming on.. 

Which has more flow based on area.  A 250 main jet (assume 250 means 2.5 mm) or a  0.12 inch needle jet with a needle that is 0.071 inch diameter needle at the end when the slide is raised all the way.. Remember the inches to mm or mm to inches conversion.. 
Max

What flows more? Your comparison is a main jet size/dia compared to a needle dia and needle jet dia?
Basics first. If you have a given needle and needle jet and you increase the size of the main the engine will run richer.
Can't change that.
Now if you increase the dia of the needle and/or decrease the diameter of the needle jet the engine will run leaner.
Can't change that.
Not sure what your point?
Bob

[PanHeadRed]

Run # 4 is a 200 main stock needle with 2 shims (#4 SS flat washers)
Run #25 is a 250 main with the same stock needle no shims.

Weather the AFR reading is correct or not you can see that run #25 is much richer then run #4. The TQ and HP is about the same. IMO within the margin of error of the machine.

The runs are all on the same day (between 1pm and 4pm) same Dyno same operator. If it's necessary for me to post the date, weather conditions, and time stamp I will be glad.

What does it mean?

[FLTRI]

Run # 4 is a 200 main stock needle with 2 shims (#4 SS flat washers)
Run #25 is a 250 main with the same stock needle no shims.

Weather the AFR reading is correct or not you can see that run #25 is much richer then run #4. The TQ and HP is about the same. IMO within the margin of error of the machine.
What does it mean?

Well it means the bigger the main jet the more fuel and the richer the AFR, notwithstanding the needle's position @ WOT.

[Admiral Akbar]

What flows more? Your comparison is a main jet size/dia compared to a needle dia and needle jet dia?
Basics first. If you have a given needle and needle jet and you increase the size of the main the engine will run richer.
Can't change that.
Now if you increase the dia of the needle and/or decrease the diameter of the needle jet the engine will run leaner.
Can't change that.
Not sure what your point?
Bob

Ok, lets get back to basics.. Ignore the needle for now an humor me (right now that may be pretty hard ).. Lets say you had a tube that is equivalent to a 500 main the is flowing a liquid.. at each end of the tube you have a jet... One is a 200 and the other is a 225.  You flow x  mls per minute.. If you change the 225 to a 250 is flow going to increase?

Max

[FLTRI]

What flows more? Your comparison is a main jet size/dia compared to a needle dia and needle jet dia?
Basics first. If you have a given needle and needle jet and you increase the size of the main the engine will run richer.
Can't change that.
Now if you increase the dia of the needle and/or decrease the diameter of the needle jet the engine will run leaner.
Can't change that.
Not sure what your point?
Bob

Ok, lets get back to basics.. Ignore the needle for now an humor me (right now that may be pretty hard ).. Lets say you had a tube that is equivalent to a 500 main the is flowing a liquid.. at each end of the tube you have a jet... One is a 200 and the other is a 225.  You flow x  mls per minute.. If you change the 225 to a 250 is flow going to increase?

Max

So your saying the needle is so big in diameter it crowds the needle jet to the point where that combination becomes the virtual main jet, meaning that a going from a 225 to a 250 will not make it richer.
So the homework assignment is to remove your main jet and see how it runs on the needle and needle jet.
Bob

[Admiral Akbar]

So the homework assignment is to remove your main jet and see how it runs on the needle and needle jet. Wink
Bob

The problem is, I don't have a CV with this problem.    Max

[FLTRI]

The problem is, I don't have a CV with this problem.    Max

Who does? I thought you were saying this is a problem with tuning these carbs. I have not found the anomaly you refer to be a problem.
Looks like bigger jet is richer in this instance as well,
Bob

[Sonny S.]

OK.....gotta good one 

I am testing AFR with a WEGO III AFR meter.
Rear pipe is leanest...checked both.

Problem :
No matter what needle is used it keeps going lean 15.5-16:1 at 3/8 throttle, mostly 75-80MPH +/- when rolling on the throttle in 5th gear. Worse on steady incline. Can hold the throttle stready when it goes lean, and it will stay lean. Now.... 1/2 throttle to WFO is fine  .  Lower gears steady throttle all through the range is fine. I can hold 3rd and 4th gear 3/8 throttle at 3-4K RPM's and AFR is fine.
I have tried different needles, jet's and springs. I have shimmed needles.
I have tried more and less discs in the pipe. I can richen it up to where it gets better but then MPG goes to chit, and it's pig rich everywhere else.
I have tried another O2 sensor, and even a MAP sensor and different timing MAP.

Could the lean condition be reversion? Am I chasing a ghost ? It does the same thing on the front pipe but not as bad because it's richer.


95"
Ported heads
TW37
Supertrapp Supermeg closed cap 20-24 discs
CV44
DTT

HELP !! 

[Sonny S.]

I had a feeling this would stump y'all.......got me    for sure

[Admiral Akbar]

Don't stump me.. I just don't read this section enough..

anyway it's the heads...




just kidding ...

It's the pipe..

Probably true..

Anyway. try filling the top row of holes in the emulsion tube with solder.

Max

[Sonny S.]

Ok I'll try it tomorrow.

Thanks for the suggestion Bruce   

Funny things is......I stuck another carb on for kicks... a CV40 that had been run before with this pipe and cams......sorta does the same thing.
Back to the heads ?  lol

[Sonny S.]

I soldered the 2 top holes shut....one on each side. Think thats what you ment and not the 2 top holes on each side. That along with a light spring and " M " needle has my problem area looking good. However, light cruise ( 1/8 throttle ) is very rich....12.2, and WFO is now 11.5. I think thwe DJ spring is what has my light cruise so rich but it's working everywhere else. Was thinking about soldering the next 2 holes and going back to stock spring.
For now I'm going to go down on the main and the pilot. Was going to do that now but forgot to bring them with me to work
That would put me in a 46 pilot. I can get it to idle ok there using an aftermarket mixture screw.

[Admiral Akbar]

That's what I would do.. Drop the pilot and the main.. See how it works.. Max

[Sonny S.]

OK, right now I'm at a 48 pilot / "L" needle / stock spring/ 226 main....soldered tube. It's a little lean again in the 3/8 throttle problem area. I tried a 46 pilot with the "M" needle and it was still a little rich down low.
Here's the deal. AFR is " safe " overall, and I am leaving on a 4 day trip in the AM with this bike. Temps are 95-98* here and humid so there ain't no air anyway...lol.
Plugs look good and no pinging. Gonna run it as is on this trip and see how it does. Knowing me when I get back I'll put the WEGO back on and get back to work.....yes it's friggin work

Thanks again for the input Bruce !   

[Scurvy]

What is your bike & build and what are the carb specs ?  CV44 ONLY
Do you have AFR data or a dyno sheet ?  If not, that's fine.

Thanks,
Sonny

New build, CV44 unmolested.
Baisley superstock heads
S&S 4 3/8 stroke flywheels
Cylinders bored to 3.92" w/Wossner forged pistons dished by Dan.
107 cu.in. @ 9.7:1 static, 180 CCP at 3700 feet.
Starts quick, warms up fast. No popping on decel. Until she's broken in, I won't try the WOT in 4th, backing off just enough to see if she surges or not.
1st tank on break in yielded 42 mpg. I think she's good for better gas mileage, but not sure where to start. Thinking the needle.
Not like the answer doesn't reside in the last few pages, I just haven't read 'em all yet.

[Sonny S.]

Haven't had time to mess with it lately but it's still lean in the same throttle position even with the emulsion tube holes soldered shut. That sorta acted like a richer needle would and richened up the 1/4 throttle and up range. I'm not sure what else to try short of sanding a needle myself.

Anyway, no time to play with it right now....have been riding it though, and all is save. However it still isn't right.

Any other ideas I can try later ?

Anyone have a Woods KT3 needle they would like to let me borrow ?

[hrdtail78]

There is no reason not to sand the needle.  I would drill out solder first.  Since it didn't help I would allow them to emulsify.  Can you step off the bike and get a slide location.  Might try adjusting MAP for that rpm and throttle.   I'd guess you are right on the transition of flat and tapered.

[Older-twin]

Shovelhead build details:
82.67 cid
Wiseco 9.5:1 pistons
S & S heads, dual plugged, ported, polished
Spyke single fire ignition with 2-80kv ignition coils,
Leinweber L51 solid lifter cam, stock ratio roller rockers. 
Cycle Shack dual exhaust with turn out tips, baffle still in place.

The preliminary 44 mm cv setup has a 46 pilot and 190 main jets.  The needle is whatever comes from the MoCo, maybe an "M".  I did some WOT main jet testing and didn't get any lean surging, and power seemed to be great.  The 46 pilot is a little big I think because I couldn't get a rich stumble when I turned out the air screw nearly 4 1/2 turns out.  It does go lean and stumble at 1 1/2 turns out from the bottom.  There was some mid-range hesitation at times, and I haven't figured out if it was from going rich or lean yet.

[Don D]

It is lean in the pilot range. Go up. It should just get rough when the needle is near the bottom, 0 turns
Use the Mikuni tuning guide to test WOT. I suspect lean there too.
Small motor less velocity / draw than typically seen by this carb on 95"+ Twin Cams

[Older-twin]

There was a 48 pilot in there and that did the same thing as the 46 is doing; the air screw turned almost all the way in will get the lean stumble.  Turning the screw out 4+ turns only made the idle go up a little.  So I was thinking that I was still too big on the pilot size, per the HSR manual instructions.  But maybe I am heading in the wrong direction, and need a 50 pilot to get the overly rich stumble with the air screw out 3 turns or more?  That may fix the mid range hesitation I was getting once in a while also.

[FLTRI]

Guys!
Simply put, use whatever pilot that gets best idle @ 1-2 1/2 turns out.
This is, IMO, the best way to decide what size pilot to use.

So, if best running occurs with the screw more than 2 1/2 turns out the pilot is too small.
And if best running occurs with the screw close to shut the pilot is too big.
IME the best tuning practice is one change at a time is key to tuning success,

HTH,
Bob

[mayor]

There was a 48 pilot in there and that did the same thing as the 46 is doing; the air screw turned almost all the way in will get the lean stumble.  Turning the screw out 4+ turns only made the idle go up a little.  So I was thinking that I was still too big on the pilot size, per the HSR manual instructions.  But maybe I am heading in the wrong direction, and need a 50 pilot to get the overly rich stumble with the air screw out 3 turns or more?  That may fix the mid range hesitation I was getting once in a while also.

I'm not quite sure if I am following what your doing, but adjusting the CV pilot is the exact opposite of adjusting the Mik pilot.  In a CV44, in is leaner.  In a MIk, in is richer.   

Guys!
Simply put, use whatever pilot that gets best idle @ 1-2 1/2 turns out.
This is, IMO, the best way to decide what size pilot to use.

So, if best running occurs with the screw more than 2 1/2 turns out the pilot is too small.
And if best running occurs with the screw close to shut the pilot is too big.
IME the best tuning practice is one change at a time is key to tuning success,

I agree with everything..except, I think it is more than acceptable to use a screw turned out up to 3 1/2 turns.  Anything past there is iffy, since the screw can and will fall out if you go too far. 

[Older-twin]

Thanks Mayor.  I had never realized that they were opposite.  I put a 50 pilot in there and it still adjusts without going too rich when the air screw backed almost all the way out.  It seems to run good at idle, and no lean pops or rich stumbles at throttle blips.  Then I started working on the main jet issues.  I started with a 190 and got more pull going up to a 210, wih no lean surging using the roll-off throttle method.  The bigger jets have fixed the mid-range flat spots I was getting.  But now it pops in the exhaust at WOT when it reaches 5,500-6,000 in the lower gears.  It may have done this before, as I don't think I was trying to run it up in RPM 'as far as it would go.' Does this seem like I am going lean at high RPM's even though it seems to pull harder?  I don't want to drown it by going too rich and I can't find this answer anywhere on the net...

[mayor]

I'm not up on what's typical for a shovel, but if i mind correctly they have sort of large ports so I would expect them to need larger jets than their TC and EVO cousins.  I wouldn't be surprised at all of you needing a 50 pilot.  I wouldn't even be surprised at you needing a 52.    

[FLTRI]

...it is more than acceptable to use a screw turned out up to 3 1/2 turns.  Anything past there is iffy, since the screw can and will fall out if you go too far.

Really the only reason 3 1/2 turns is, IMO, too far out, not because it won't work.
Bob

[Older-twin]

How is a good way to know when I am dumping too much gas with the main jet (by the seat of the pants method)?  I have gone up from 190 to 210 in the main jet and not getting the "lean surge" on roll off tuning so I keep going up in size, but I get popping out of the exhaust at 55-6000 RPM's when I wind it up past 5k in the lower gears.  Is this a lean condition at that RPM with a decent cam (Leinbeber l51) as it breaths at those RPM's?  Or is it an overly rich condition that only shows itself at those RPM's?  Please post some experiences for me and other carb enthusiasts searching for answers...

[05FLHTC]

WOT test is the way I do it.

Decrease the main until letting off the throttle shows an increase in engine RPM's then go back up 1 or 2 jet sizes.

Then adjust the needle until the mid range starts to lean surge hunt a little, then add a shim or 2 finish up with the pilot...redo until yr heart is content. Then finish up by spending the $ for a base dyno run to confirm AFR #'s done.

Here read this it works...

http://www.mikuni.com/fs-tuning_guide.html