Hello.
So my mild Evo may have a bit of jetting problem but unfortunately my dealer is fully booked until August.
The symptom is that FLHR starts cold or warm very easily, cold start requires a bit of choke and it takes a while to be able to push it back in. Engine, when above say 2500 rpm pulls well but from around 2000 or so it is very hesitant and slow to pull. Accelerator pump works.
I thought first that there is a way too big cam in otherwise stock engine but I'm not so sure anymore if the cam is that big afterall. Pulling a bit of choke does not improve the situation.
I checked pilot screw yesterday and it was just half a turn open from closed. I opened it to two full turns. It did not go worse but not better either.
I pulled the carb today and main jet is 165 (with our gas we seldom need a bigger one on mild builds) but the pilot jet was 48. Isn't that quite big? Should I put in a 45 instead?
The other question is:
The Keihin is otherwise stock. When the time comes to have it dynotuned we may need Dynojet or Thunderslide kit + something else.
CV40 has always been good and plenty enough for me but I got an offer for a brand new Mikuni HSR42 Easy Kit and it IMHO is a bargain.
Instead of working on the old Keihin would getting the HSR42 instead bring any negatives to how the engine runs as long as the carb is jetted correctly? My mechanic is familiar to work with Keihin and Mikuni.
Despite of what cam we eventually will find from there it will be replaced with an Andrews EV13.
The cv carb works well with an Evo with a cam. You might try a 44 pilot if you can find one, 45 might work, might go back to a 42 once you start getting into it.
Your cold start with the choke on sounds like it is working properly, my bike gets full choke at cold motor start up every time, warm or cold weather.
The hesitation at 2000 rpm, is that in 5th gear, or first gear? If fifth gear, that is too low of an rpm to try and do a hard acceleration, downshift to get into mid/high 2000's rpm.
If hesitates in 1st gear when warm, check for vacuum leaks, change that 48 out.
No experience with Mukini carb, but they are a very good carb, it's not necessary with with your mild set up, but it will work well when tuned. Probably won't get as good fuel mileage as the CV, if that matters.
:agree: What Hoss said.
It feels like it "lacks" in every gear in lower register. Difficult to to describe. Seems to pull better if I open throttle more. Unfortunately I do not know yet if slide has been drilled and if there is a stock spring in there. I'll try the 45.
There is no pinging but who knows how the 2000i ignition is set up now. Has to be checked.
With Dyna 2000i are you supposed to retain VOES?
Do not drill the slide. If it is already done, consider getting a new oem replacement. Stick with stock spring.
I would shy away from the Thunder slide kit.
That 48 is causing much of your sluggishness.
Thanks guys, much obliged. :up:
I have a Mikuni HSR-42 on a 94' FLHTC. I put it on in 1995 or 1996 and have zero complaints. Very easy to tune, and response is greater than the CV that I had on there. I did a bunch of modifications to a few CV's that I tried on there. Stock Slide, Drilled the Slide. Stock Spring, Different Spring, Many Jetting combinations, Sportster Needle, etc. None of that compared to the Mikuni in performance with minimal tweaking as far as I'm concerned.
I have used an HSR42 as well as the CV40. after screwing around with jetting on the Mikune, I ended up with it the way it came out of the box. In order to for a CV40 to work properly the intake seals must not leak.
find 46
all good
Finn, being in Europe you may find it cheaper to buy a Mikuni HSR42 kit than a new CV40.
I bought my HSR42 from the USA, paid the usual UK VAT and import duties and it was still a lot cheaper than the new CV40.
I take it you don't want to use a worn out old CV40 any more than I did?
Nope, I will not get a new CV. If we get this one sorted then that's OK but if there are problems with jetting (like we had on my Bad Boy) then HSR42 it is.
Got an offer from my dealer of 555,- Euros for an Easy Kit and for me it is reasonable.
As it turns out, while I visited them today to pick up the 45 pilot jet, they found me a slot for next Monday for jetting. Yay! If we do not get the jetting OK we will order the Mikuni.
Hopefully this CV don't respond too well to jetting changes... :teeth:
Quote from: fidel on June 19, 2022, 10:16:05 PMfind 46
all good
A 46 is probably too big for an Evo 80".
There is no comparison to the throttle response of the HSR42 and easy to tune
Now you're going to make me get a Mikuni to replace my worn out CV.
Damn you guys.
Quote from: Hossamania on June 20, 2022, 07:48:40 AMNow you're going to make me get a Mikuni to replace my worn out CV.
Damn you guys.
Ha-ha...Gotcha'
Smaller engines can want a larger jet than what you might think because it's not pulling as hard on the carb, nothing wrong with trying a 46 pilot on an evo. I don't get the feeling that it will help your symptoms and would be taking a peek at what cam is in it
The HSR42 is my favorite, would also recommend to install the lean out kit in it, before you put it on.
CV's are good, cheap and easy to work on, but the HSR42 is still my go to carb.
42 HSR. My go to carb on Sportsters, Evos, and mild Twin Cams. 45 on mod. 95", 103".
John
I had a road king with head work , cam ,slip on running the cv with a 50 low and 200 high jet . had it dyno tuned and the guy who did it said that the cv is good to 90hp , he has bored them to 42 uses mik on bigger motor like 95 then goes with the 45 mik.
I would only use the HSR42, it's a much better carb than the CV. It will change your bike.
Small things but I changed the pilot jet to 45 today.
After brief test it is completely different bike. And the jetting is not yet even close to what it should be.
Now the cam - what ever it is - no longer feels that hot anymore.
The only reason you'd get worse mileage with the mikuni is because of your right wrist lovin' the throttle response of the cable operated slide and better tunability of it over the cv. Hands down a better carb.
Oh, the fact you have the idle circuit screw a half turn out only is a real good indication that 48 pilot is too big. The stock 1200 sporty came with a 180 main.
You don't mention the needle. An '88 sporty needle would be a good choice.
I wouldn't think twice about jumping on that hsr42 tho.
Quote from: 60Gunner on June 22, 2022, 04:27:47 PMThe only reason you'd get worse mileage with the mikuni is because of your right wrist lovin' the throttle response of the cable operated slide and better tunability of it over the cv. Hands down a better carb.
Oh, the fact you have the idle circuit screw a half turn out only is a real good indication that 48 pilot is too big. The stock 1200 sporty came with a 180 main.
You don't mention the needle. An '88 sporty needle would be a good choice.
I wouldn't think twice about jumping on that hsr42 tho.
Are you spying on me? :chop: :baby:
Right.
We had a dyno session today to check the mixture and to hopefully get it sorted.
Right from the start the CV40 was hopelessly lean. But that could be corrected until point when we ran out of parts ie. needles.
The (for the moment) end situation was pilot jet around 46...47, main around 175 and needle N86E (it was in) with two washers under it.
This is how it did:
https://i.imgur.com/2sy5N5t.jpg (https://i.imgur.com/2sy5N5t.jpg)
As I mentioned we ran out of needles and perhaps also time.
This is of course full throttle graph - on the road it feels really good with part and/or full throttle.
Our question is: Which needle should we use to richen the area below 3000 rpm?
My earlier experience of tuning the CV40 with Dynojet kit was not very satisfactory ie. we changed parts and made adjustments but it did not react that well after certain point.
We would be quite OK with everything else if we just could richen the lower rpm area a bit.
(https://i.imgur.com/LLTimmi.jpg)
Any suggestions?
EDIT: Quickly judging by the dimensions of various needles it looks like Sportster needle N65C might be the one to try. :scratch:
I don't think you are going to be able to tune that out. It's just the nature of the beast when the throttle is wacked wide open, it takes a big gulp of air. I have a similar lean spot on this curve with a Mikuni. Here is an example on one of my Evo bikes. I tried more accelerator pump, and it helped slightly, but the problem is still there. I think it may be the sensor being affected by exhaust reversion. This has an EV13 cam, stock head pipes, and the old HD catalog slip on mufflers, HSR42. 162.5 main jet, 97 needle. You can see on these 2 sheets, that when you look at it vs time and not RPM, it is just a blip. Notice the A/F is right on, and then the dip, and it's back to right on. You can't notice it on the bike, so that's why I think it's just the reversion affecting the sensor.
Yes, I'm starting to agree on that being difficult to iron out.
I'm still tempted to try CV Performance Velocity needle (https://cv-performance.com/cvp-velocity-needle) but that's about it. Unless I choose to spend the coming tax return on a Mikuni... :smilep:
Quote from: Finn on July 06, 2022, 12:10:21 PMYes, I'm starting to agree on that being difficult to iron out.
I'm still tempted to try CV Performance Velocity needle (https://cv-performance.com/cvp-velocity-needle) but that's about it. Unless I choose to spend the coming tax return on a Mikuni... :smilep:
I used that needle in my CV40 on a 2001 88" Stage I Twin Cam with 45/190 jets. I had the N65 needle and didn't like the way it ran......
I put that CV performance needle in my carb and it now runs excellent in my set up...
That is good to hear. :up:
We should know tomorrow how it works on mine. Got EV13 + lifters + needle bearing etc. done today. Jetting and such is for tomorrow.
When I was riding 100 km trip to my dealer this morning I was all smiles as the bike ran so well after last re-jetting: no pinging, pulled very well from low rpm and barked really nice when opened throttle a bit more.
One thing was sure: the cam in there was not stock but even the previous owner did not know anything about it so that was going to be interesting. My money was on EV13 or 27 but all sorts of other possibilities were on table, too.
Well, there was an Andrews 27 with stock (probably original) lifters and plastic breather gear in.
My mechanic said that that is a surprise as everything points to stock compression ratio and his experiences of 27 + stock CR have been fairly negative and my bike ran very well. We will see how the heads look come winter.
I had my mind set on EV13 as I want a workhorse and plenty of low to mid range TQ.
New Feuling lifters and needle bearing and S&S steel breather will give peace of mind for years, I hope.
I was quite clean inside after Valvoline VR1:
(https://i.imgur.com/4sOyB71.jpg)
FWIW, with Andrews EV13 Evo made today 72 hp @ 5390 rpm and 82 ft-lb @ 3980 rpm. These are pretty much exactly same numbers as with EV27 plus/minus 1 hp/tq. Compression ratio is stock.
On the road 27 "felt" like it had more mid range although dyno graph says otherwise. The EV13 is a "rubber band" ie. torque is always available whenever you need it. And pulls nicely with higher rpms, too.
We had earlier big problems with jetting with original needle. Now CV Performance's Velocity Needle corrected the problems. We ended with CVP needle without shims, 46 pilot and 205 main.
A bit strange the 205 but she asked for more fuel so we needed go up in size.
Touring cam the EV13 but still gives a nice rumble. :up:
Glad you got it dialed in. That 205 is much bigger than I would have guessed necessary, interesting result, good hp and tq numbers.
Have you had a chance to check mileage yet?
No, not yet. They got it ready late in the afternoon and I then just rode back home 100 km. I'm going to spend whole weekend on it so will soon know the mileage.
FWIW, mpg seems to be around 40 in mixed riding.