Author Topic: Jets EV27  (Read 1273 times)

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Online 1FSTRK

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Re: Jets EV27
« Reply #25 on: February 11, 2018, 02:31:13 PM »
Nope.
If the rear runs richer and the front runs leaner ...
There is not a dam thing i can do except make sure the front is not the lean one.
If one wishes to put in an extra bung, they  could swap the sensor around from time to time.

That's a big if

No its not.  Every tuner knows the rear cylinder needs less fuel as it is plain as day in the fuel tables. Bikes with carbs are no different in that regards.

I understand it says that in all the books because of the design of the engine but in real life things like exhaust design, head flow, and individual cylinder compression also play into tuning.

Offline thumper 823

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Re: Jets EV27
« Reply #26 on: February 11, 2018, 02:51:35 PM »
Quote from Turbo prop-"No its not.  Every tuner knows the rear cylinder needs less fuel as it is plain as day in the fuel tables. Bikes with carbs are no different in that regards."
end q


Yea and everyone knows this, and that  is just another way of saying it--...
I had this discussion one time in another life
yes, the rear runs richer so it would need less fuel.
The Caveat is the front runs leaner.
Now what ya going to do?
Try to aim the carb for optimum?
Run two carbs?
Switch to fuel infection?
I am happy where I am at..untill next spring anyway when i get the heads back on .
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Offline turboprop

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Re: Jets EV27
« Reply #27 on: February 11, 2018, 02:56:58 PM »
Nope.
If the rear runs richer and the front runs leaner ...
There is not a dam thing i can do except make sure the front is not the lean one.
If one wishes to put in an extra bung, they  could swap the sensor around from time to time.

That's a big if

No its not.  Every tuner knows the rear cylinder needs less fuel as it is plain as day in the fuel tables. Bikes with carbs are no different in that regards.

I understand it says that in all the books because of the design of the engine but in real life things like exhaust design, head flow, and individual cylinder compression also play into tuning.

Regardless of any of those things, an air cooled harley, the rear cylinder will always run richer or need less fuel than the front. Always. Thats from experience, not read online.
'The Thread Killer' - Worn with pride.

Offline thumper 823

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Re: Jets EV27
« Reply #28 on: February 11, 2018, 03:01:35 PM »
Nope.
If the rear runs richer and the front runs leaner ...
There is not a dam thing i can do except make sure the front is not the lean one.
If one wishes to put in an extra bung, they  could swap the sensor around from time to time.

That's a big if

No its not.  Every tuner knows the rear cylinder needs less fuel as it is plain as day in the fuel tables. Bikes with carbs are no different in that regards.

I understand it says that in all the books because of the design of the engine but in real life things like exhaust design, head flow, and individual cylinder compression also play into tuning.

I have yet to find another bike running around with a AFR gauge in it, much less a way to monitor both cylinders.
My point is, i watch mine every trip, not just once on a dyno..then there are as the original argument- those that dont need one at all !
( I laugh)
I have not bought a dyno yet,  so those here that are all of a sudden experts please tell me the common number the rear is off by .02?  or a whole point?
I will run mine on a dyno this Spring, will they monitor both cylinders?
How will the do that with just one bung?
how do they know anythig when most bikes have none?
Or two into one and no bungs,
or
 Two exhaust pipes , how would a dyno guy know?
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Offline thumper 823

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Re: Jets EV27
« Reply #29 on: February 11, 2018, 03:03:24 PM »
Nope.
If the rear runs richer and the front runs leaner ...
There is not a dam thing i can do except make sure the front is not the lean one.
If one wishes to put in an extra bung, they  could swap the sensor around from time to time.

That's a big if

No its not.  Every tuner knows the rear cylinder needs less fuel as it is plain as day in the fuel tables. Bikes with carbs are no different in that regards.

I understand it says that in all the books because of the design of the engine but in real life things like exhaust design, head flow, and individual cylinder compression also play into tuning.

Regardless of any of those things, an air cooled harley, the rear cylinder will always run richer or need less fuel than the front. Always. Thats from experience, not read online.
And that is what i stated.
D Troop 3/5, - C/16 ,162AHC, Mekong delta.
Amateur engineering with bad math.

Online shovelbill

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Re: Jets EV27
« Reply #30 on: February 11, 2018, 03:07:45 PM »
Quote from Turbo prop-"No its not.  Every tuner knows the rear cylinder needs less fuel as it is plain as day in the fuel tables. Bikes with carbs are no different in that regards."
end q


Yea and everyone knows this, and that  is just another way of saying it--...
I had this discussion one time in another life
yes, the rear runs richer so it would need less fuel.
The Caveat is the front runs leaner.
Now what ya going to do?
Try to aim the carb for optimum?
Run two carbs?
Switch to fuel infection?
I am happy where I am at..untill next spring anyway when i get the heads back on .

ACTUALLY YEA.....MACHINE THE INTAKE FLANGE 3* TOWARD THE FRONT......I'VE ALSO RAN REAR CYLINDER COMPRESSION ABOUT 1/4 POINT HIGHER COMPRESSION.....SMOOTHED THE MOTOR OUT......HEAD TEMPS EQUALIZED.

sorry for the caps.....i didn't know the cap button was on and wasn't gonna re-type this.

hope this gives a little different point of perspective.
build it, bust it.....figure out why

Offline thumper 823

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Re: Jets EV27
« Reply #31 on: February 11, 2018, 03:11:29 PM »
what was the difference between front and rear B4 you did this?
At what throttle setting?
Or, was it linear?
D Troop 3/5, - C/16 ,162AHC, Mekong delta.
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Offline Evo160K

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Re: Jets EV27
« Reply #32 on: February 11, 2018, 03:49:09 PM »
Quote from thumper 823:
I have yet to find another bike running around with a AFR gauge in it, much less a way to monitor both cylinders.
My point is, i watch mine every trip, not just once on a dyno..then there are as the original argument- those that dont need one at all !
( I laugh)
How will the do that with just one bung?
how do they know anythig when most bikes have none?
Or two into one and no bungs,
or
 Two exhaust pipes , how would a dyno guy know?
[/quote]


I do it with a Dual Throat carb on an Individual runner intake manifold with dual bungs and dual afr gauges.  Let's me adjust the afr for power or economy on the fly.  Very entertaining




Online 1FSTRK

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Re: Jets EV27
« Reply #33 on: February 11, 2018, 04:04:16 PM »
Nope.
If the rear runs richer and the front runs leaner ...
There is not a dam thing i can do except make sure the front is not the lean one.
If one wishes to put in an extra bung, they  could swap the sensor around from time to time.

That's a big if

No its not.  Every tuner knows the rear cylinder needs less fuel as it is plain as day in the fuel tables. Bikes with carbs are no different in that regards.

I understand it says that in all the books because of the design of the engine but in real life things like exhaust design, head flow, and individual cylinder compression also play into tuning.

Regardless of any of those things, an air cooled harley, the rear cylinder will always run richer or need less fuel than the front. Always. Thats from experience, not read online.
And that is what i stated.

Ever been to the HD dealer and hear them tell a customer "they all do that"
I realize if all you have ever seen is all you go by then you could get that attitude.
But if you always do what you have always done, you will always get what you always got.
I have seen first hand that they do not all run richer on the rear. I will not try to change your minds.
Good day and good luck

Offline thumper 823

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Re: Jets EV27
« Reply #34 on: February 11, 2018, 04:14:41 PM »
I am still waiting for the answer -what is the difference in AFR from the front to the rear??
Yes i know the rear runs richer.
Or you can say the front runs leaner.
That is why I always have paid more atn to the front plug or nowadays the front cylinder AFR.

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Offline thumper 823

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Re: Jets EV27
« Reply #35 on: February 11, 2018, 04:18:19 PM »
Quote from thumper 823:
I have yet to find another bike running around with a AFR gauge in it, much less a way to monitor both cylinders.
My point is, i watch mine every trip, not just once on a dyno..then there are as the original argument- those that dont need one at all !
( I laugh)
How will the do that with just one bung?
how do they know anythig when most bikes have none?
Or two into one and no bungs,
or
 Two exhaust pipes , how would a dyno guy know?
[/color]

I do it with a Dual Throat carb on an Individual runner intake manifold with dual bungs and dual afr gauges.  Let's me adjust the afr for power or economy on the fly.  Very entertaining
[/quote]
99.9 % of the population does not have that nor wants it.
So dialing in a rear cylinder is not the most economical to do for most people.
I will bet mine is less then a 1/2 a point from the front
What are you getting for TQ and HP for that configuration? (and size engine?)
D Troop 3/5, - C/16 ,162AHC, Mekong delta.
Amateur engineering with bad math.

Offline Deye76

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Re: Jets EV27
« Reply #36 on: February 11, 2018, 04:18:33 PM »
"Now what ya going to do?
Try to aim the carb for optimum?
Run two carbs?"

My point. Answering the original post like Don did, with a CV carb, somewhat limited. Absolutely nothing to do with a dual throat carb. Sheesh, riding is supposed to be fun.  :chop:
East Tenn.
2014 CVO RK, 2015 RGS, 1992 FXRP

Offline thumper 823

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Re: Jets EV27
« Reply #37 on: February 11, 2018, 04:25:37 PM »
I ride about 1oK per year, Sturgis every other , yes I have some fun.
My top end is pretty much on the edge and I prey to get 20K out of it . (valves mostly)
But back to the mainstay of main jets here -
There will always be backyard hoodlums that still talk about "plug checks"
Most when quizzed do not really know how to do that either.
They are not smokey Yunicks
Neither am I, that is why I have the AFR meter.
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Offline Deye76

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Re: Jets EV27
« Reply #38 on: February 11, 2018, 04:32:20 PM »
If we're going to tell about our experiences, I put a over 90,000 miles in 4 years, on my 1988 Electraglide Sport, in elevations from Michigan to Banff and Lake Louise and all the mountain ranges in the USA in between, on a stock Kehin carb, no AFR gauge, not a hiccup, still going strong when the bike got stolen in 1992.
Edit: Would it have won a dyno shootout, no, didn't care.
« Last Edit: February 11, 2018, 04:42:46 PM by Deye76 »
East Tenn.
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Offline Evo160K

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Re: Jets EV27
« Reply #39 on: February 11, 2018, 04:55:54 PM »
97"
Here's what the previous 97" was doing, I think the current 97" (S&S case and lower end) is a bit stronger.  99.9% of the population never had the patience to tune the Weber's and Dellortos when they were popular some years back, but they're awesome looking and running carbs when they're tuned.  The af gauges have made that possible.

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Offline thumper 823

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Re: Jets EV27
« Reply #40 on: February 11, 2018, 05:07:24 PM »
Those are nice numbers.
 i thought the problem with twin carbs and or barrels is the port velocity is not shared very well or at all ?
D Troop 3/5, - C/16 ,162AHC, Mekong delta.
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Offline Evo160K

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Re: Jets EV27
« Reply #41 on: February 11, 2018, 06:25:43 PM »
@ thumper 823,
Thank you.
Since the flow with an individual runner manifold is separate, there is no sharing of port velocity.  I have no experience with shared flow manifolds, so I can't comment on shared port velocity other than to say, I suspect you're comment is correct .

@ Prostock,
When I was running a cv on an 80", I used a 46 pilot jet with a slightly sanded needle, which is like shimming, and adjusted for smoothest idle.  That more or less is exactly what H.D Street performance is suggesting.  Btw, iirc, joe minton, the motojournalist/h-d wrench, used to say he never saw an evo that needed anything but a 46 when set-up properly.  Someone chime in if my recollection of his comment is incorrect.

Offline JW113

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Re: Jets EV27
« Reply #42 on: February 11, 2018, 08:39:38 PM »
Are you saying it is 'better' that the two cylinders share a manifold and carb? That sure is not how virtually ever other motorcycle in the world except HD is set up, now is it? Even in HD land, the XR750 and XR1000 uses two carbs and no shared manifold, and they're supposed to be the 'performance' Harley Davidsons.

There is more to tuning without an AFR meter than just looking at the plugs. Full throttle pulls with back off, monitoring fuel mileage, sound of exhaust note during deaccel, RPM drop with idle needle jet, color of the exhaust pipe outlets, among others. I'll say it again, get it close enough to get the job done, then ride it and don't worry. It's like tire pressure. I'm sure you can rig your tires up so you can read the pressure while riding the bike, and I'm sure there is some "optimum" tire pressure. Speaking for me only, ain't that concerned. Bike seems to work just fine somewhere between 34 and 40psi, and I can't even tell they're low until they get below 30.

RE: 46 pilot jet. Never used one, only 45 or 48. The idle needle can correct if the 45 is not rich enough. Which for a mostly stock motor, 45 pilot works great.

-JW
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1945 Indian Chief   1978 XL Bobber

Offline thumper 823

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Re: Jets EV27
« Reply #43 on: February 12, 2018, 01:10:34 AM »
Ok folks -I am not the internet king and almost know nothing and i can prove it most the time.
What I do know is from the Porsche world where we raced and hung out on dynos and blah blah.
 -and some went to the wine and cheese tasting farms afterward..LOL
That all said -
A  HD engine is just like a Porsche engine only different. 
A LOT different.
Double carbs (ONNE PER CYLINDER )as I know them will work, but only at the RPM that racers use , where port velocity hits the sound barrier.
Notice you see them on old race cars and Porsche, one per cylinder. (read high RPM )
Even today they (carbs) are the Holy Grail for the old 911 folks.They call it backdating.
The Old HD engine is entering the hand grenade zone where these will start to perform.
The little (well not so little but smaller ) XR used them on the track.
Notice the smaller stroke? (higher velocity)
Some even had their heads turned around or backward, I cant remember, and not going to look it all up, but I  "seen" one once, so I am an expert.........LOL
The Nippondenso Jap bikes are a short stroke, again velocity.   Hence lots of carbs. 12000 RPM is an idle almost...(Ok, thats an illustration.)
'Snowmobiles until the advent of Fuel infection-again carbs.
So for me, the demarcation is real life-
I ride two up, heavy and want all the Torq I can get ...NOW.
I love blowing past bigger bikes!
I know I have the little Evo stressed to the edge and willing to eat the consequences, should she blow.
(AND SHE HAS IN THE PAST)
I do my own head work, and steal ideas as fast as I can. But the twin-carb thing - I am not a believer for my kind of riding.

Also- one has to qualify what works for most- as far as jets
My little engine is pulled dwn tight 10.5-1  double plug, ported, tiny guides.Lots of valve angles,
.o30 angled squish, re shaped combustion chamber with domed pistons.
It is an ongoing creation and I change it most ever winter.
Living on the edge takes up less room.



« Last Edit: February 12, 2018, 01:22:22 AM by thumper 823 »
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Offline Scott P

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Re: Jets EV27
« Reply #44 on: February 12, 2018, 03:52:15 AM »
My goodness, how the hell did we ever manage to tune engines before the advent of the AFR gauge?
 :hyst:

I wonder if Burt Munro used one to set that land speed record?
 :scratch:

And then, there is the cookbook method. How many Evo Fatboys were made? How many with basically stock motor with EV-27 cam? Gonna guess a few thousand, maybe more. And what was used to jet them? (ask the guys that did it, they know)

The thing I love about klunky old carburetors over fuel infection is that it's not rocket science. Get it close, and day to day the bike runs just fine if not great.

-JW

Yep.
Otto Knowbetter sez, '"Don't mistake kindness, for weakness".

Offline thumper 823

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Re: Jets EV27
« Reply #45 on: February 12, 2018, 04:20:00 AM »
Close will not work if you are on the edge ..
Plus the old experts like Smoky Yunick would have been using a AFR meter if he had one.
Carry on.
Live in arrogance or ignorance, pick one.
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Offline JW113

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Re: Jets EV27
« Reply #46 on: February 12, 2018, 07:17:02 AM »
BINGO!

On the edge? Nope. Either splitting lanes in daily commute, or steady cruise at highway speed.

Yes, close enough.
 :up:

Oh, and about those AFR gauges, particularly the cheapo ones you guys keep referring to. "Gauge R&R".

Speaking of one the edge, which in my book translates to "racing", let me ask a question to any of you drag racers that might be following this thread. Do you tune to a AFR gauge or a stopwatch?

-JW
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Offline thumper 823

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Re: Jets EV27
« Reply #47 on: February 12, 2018, 08:19:27 AM »
BINGO!

On the edge? Nope. Either splitting lanes in daily commute, or steady cruise at highway speed.

Yes, close enough.
 :up:

Oh, and about those AFR gauges, particularly the cheapo ones you guys keep referring to. "Gauge R&R".

Speaking of one the edge, which in my book translates to "racing", let me ask a question to any of you drag racers that might be following this thread. Do you tune to a AFR gauge or a stopwatch?

-JW

I do not know who, or what is the cheap AFR guage you are referring to, please point me to the one you think is a gooder one.
The wideband uses a bosh sensor and is supposed to be accurate.
i know it is fast !
Correct?
Perhaps share what you know?
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Online ecir50

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Re: Jets EV27
« Reply #48 on: February 12, 2018, 08:59:47 AM »
must be meaning narrow band as opposed to wide band

Offline thumper 823

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Re: Jets EV27
« Reply #49 on: February 12, 2018, 10:06:05 AM »
Narrowband is worthless and not even part of the equation here.
Not sure why he or anyone would reference them.
The wideband AEM  uses Bosch LSU wide band which reads about 7 times per second I am told.
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