Still cant tune my carbs

[65fury]

Okay so after redrilling my slides to have the correct size hole, i noticed i still have the stumble in the 4k-6k range, altho its not a bad stumble its still not right. Also checked my plugs and the y are finally getting a tan color to them compared to being white before i started playing with the carbs again.

Im curious tho.... at lets say 7k cruising in 3rd or 4th and i whack it, itll kinda stumble slash hesitate before it accelerates?? what would cause the stumble?? If its to rich on the top end would it stumble at WOT or would that be a lean situation??

Jason

 

[KJShover]

Im curious tho.... at lets say 7k cruising in 3rd or 4th and i whack it, itll kinda stumble slash hesitate before it accelerates?? what would cause the stumble?? If its to rich on the top end would it stumble at WOT or would that be a lean situation??

It could be one or the other.

Have you tried this method yet?

Originally Posted by maleko89
You should probably be able to accept WOT in any gear above 2K w/o any bucking or complaint.

Do the following tests.

1) Cruise at 4K in 5th gear .. hold RPM steady (count to 5) and then whack it WOT as quickly as you can. You shouldn't feel the slightest delay or hesitation. If you do, too rich. This does not work at 3.5K or 4.5K, only at 4K because the slides will start to retract at 4.5K even at the lightest throttle angle. 4K sets us up on the threshold and gives us a big jump when we whack it. there is no other RPM to do this where you will get as big a slide jump when rapidly moving to WOT.
This tests for too rich of needle.

2) Verify that starting cold .. that the engine is weak .. and will complain if you try to hold the RPM at 1800 rpms. Within 1-2 min or no later than when the temp needle touches the first mark you should be able to hold the engine between 1500 and 2K w/o complaint or popping back through the carbs. At the least you should be able to do this by the time the engine is fully warmed up but if you are more than 1/2 way between the dot and cold on the temp gauge your pilots are plugged or too lean... (clean or reduce the PAJ2). If you can hold 1.5-2K as soon as you start cold then your pilots are set too rich and you will suffer rich symptoms when it comes to operating temp (clean or enlarge the PAJ2). Only change PAJ2 bigger/smaller if you mixture screws are out or in too far already.
This is how you set your pilot mixture.

3) Do a hard WOT pull in 2nd or 3rd gear from below 3K. Look for a smooth pull all the way up. If it seems to lag in the 4-5K range then too much needle. If we sputter going past 4.5K you don't have enough needle.
This tests for needle richness and leanness.

4) Verify you can cruise "nice and deliberate" at 5K .. if you stumble around and are OK everywhere else you don't have enough pilot.
Another pilot mixture test.

As for your mains, I'd at least go to 147.5's. General rule is to subtract main jet size by 1% for every 1000 feet above sea level. So, need to decrease main jet size of 152.5 by 4.5%. 95.5% times 152.5 = 145.6. I'm thinking 145's would work best at 4500 feet above sea level.

 

[[email protected]]

If it bogs down before it takes off, but the engine feels smooth, that is usually a rich condition

If it stumbles and the eninge feels a bit rough, that is usually a lean condition

That high up in the rpms would be your mains

 

[65fury]

Well it seems like im back to square one again, anything over 4k and 1/4 throttle it sounds really poppy and kinda high pitched. then around 6.5-7k it smooths out and starts pulling hard. Im still not sure if my 4k-7k is running rich or lean... my plugs are a very light tan. I now this might sound crazy but the largest main jet ive used is the 165(which was in the bike when i bought it) plus all the floats were set so the bike would run even richer(also how the bike was when i bought it) and it ran great then. So just for kicks im going to try 170 mains or even 175s. Sounds backwards and maybe even dumb, but so far anything smaller than the 165s hasnt seemed to change anything other than the top end. Hell i got nothing to loose and itll atleast tell me what main will work the best. Since in the carb bible thread it says to chosse the best main jet first then tune from there maybe i need to go a lil bigger:ummm:

Just curious, what would breather more freely? stock headers with supertrapp slip ons 4-2 or the kerker 4-1? kerker right??

because if i think about how the bike was setup before.... it had supertrapp slip ons, stock airbox and filter(still does) drilled slides, floats set rich, and 165mains and it was stupid fast!

Now i have the kerker 4-1(slides have stock holes now) floats set at 16mm(wet) and 165 mains, but if the kerker breathes better then i need more fuel to compensate for the free flowing exhaust....right? especially since i leaned out the carbs just by setting the floats to 16mm and better exhaust...... just brain storming out loud, any other thoughts would be helpful.
I know that most everyone on here would probably disagree with going to 170 mains since that is way bigger than stock and those with my same setup have smaller mains and there bikes are running great! except mine doesnt run great with stock mains and needles....:confused2:

Thanks

jason

 

[65fury]

what if i pulled out the stock 170 PAJ2s and put in 165s or 160s... would that richen things up?? maybe have the same effect as running larger mains???? just a crazy thought.

jason

 

[Kratos]

Well it seems like im back to square one again, anything over 4k and 1/4 throttle it sounds really poppy and kinda high pitched. then around 6.5-7k it smooths out and starts pulling hard. Im still not sure if my 4k-7k is running rich or lean... my plugs are a very light tan. I now this might sound crazy but the largest main jet ive used is the 165(which was in the bike when i bought it) plus all the floats were set so the bike would run even richer(also how the bike was when i bought it) and it ran great then. So just for kicks im going to try 170 mains or even 175s. Sounds backwards and maybe even dumb, but so far anything smaller than the 165s hasnt seemed to change anything other than the top end. Hell i got nothing to loose and itll atleast tell me what main will work the best. Since in the carb bible thread it says to chosse the best main jet first then tune from there maybe i need to go a lil bigger:ummm:

Just curious, what would breather more freely? stock headers with supertrapp slip ons 4-2 or the kerker 4-1? kerker right??

because if i think about how the bike was setup before.... it had supertrapp slip ons, stock airbox and filter(still does) drilled slides, floats set rich, and 165mains and it was stupid fast!

Now i have the kerker 4-1(slides have stock holes now) floats set at 16mm(wet) and 165 mains, but if the kerker breathes better then i need more fuel to compensate for the free flowing exhaust....right? especially since i leaned out the carbs just by setting the floats to 16mm and better exhaust...... just brain storming out loud, any other thoughts would be helpful.
I know that most everyone on here would probably disagree with going to 170 mains since that is way bigger than stock and those with my same setup have smaller mains and there bikes are running great! except mine doesnt run great with stock mains and needles....:confused2:

Thanks

jason

Just my 2 cents...

When I tuned mine, I used an Innovate Motorsports DB air/fuel ratio kit. I ended up with 147.5 mains that got me in the high 12's and low 13's air/fuel ratio at WOT, which is where I want to be. After setting the floats, adjusting the needles and the fuel mixture screws where I thought it was running well and it was smooth with a WOT run from about 2.5K - 3K all the way to redline, I thought it was perfect. Then since I had made the whole mix quite a bit more lean than it was, I had an idling issue. Seemed kind of erratic, wouldn't idle very smooth no matter what the settings were. I then first did the shotgun cleaning method a few times, no luck, then took the carbs apart and cleaned them more thoroughly and bingo, the idle was smooth again. Well, took it down the road, and then at part throttle it was doing just as you describe. Evidently whatever was clogged in the carbs was causing to run rich, since now that they were clean, I was running into a lean condition at part throttle. I sync'd the carbs several times because the problem seemed to be more related to throttle position than anything else. I tried turning the fuel screws out, but they didn't have much of an effect even at 5 turns out. After riding more, I noticed that if I made a WOT run and backed the throttle off slightly during the run, it would actually pop and fall on it's face, then as I close the throttle further, it was fine. So to me that meant it was something other than the pilot circuit. The last thing I tried was to richen up the needles. I raised the needles 1 position and both issues were resolved. I'm not sure if that was the correct way to fix the issue, but the bike seems to be running perfectly now.

 

[65fury]

hey thanks for your 2 cents. Im up to try anything and im going to try and find someone with an air/fuel gauge to try on my bike and see what im at. i also notice when im at WOT and i let off the throttle just a bit it seems to stop stumbling and smooth out, until i twist it past 1/4 throttle then it flubbs all the way to 7k and then gos!! If i pull the "Y" or run without the tanks cover and try to lean things up it runs like crap from 4k and up.... which leads me to believe it is still a lean issue in my midrange.. im going ot try larger mains tommarrow and see what happens.... who knows maybe it will help and ill end up running some 200mains!!:rofl_200:

Jason

 

[Kratos]

hey thanks for your 2 cents. Im up to try anything and im going to try and find someone with an air/fuel gauge to try on my bike and see what im at. i also notice when im at WOT and i let off the throttle just a bit it seems to stop stumbling and smooth out, until i twist it past 1/4 throttle then it flubbs all the way to 7k and then gos!! If i pull the "Y" or run without the tanks cover and try to lean things up it runs like crap from 4k and up.... which leads me to believe it is still a lean issue in my midrange.. im going ot try larger mains tommarrow and see what happens.... who knows maybe it will help and ill end up running some 200mains!!:rofl_200:

Jason

Good luck man, I fought with mine for quite a while before I got the A/F kit. The A/F gauge is the best thing to do, you will be able to work with actual data rather than trying to guess what is going on. Some of the symptoms seem to be so misleading, there is no way to figure them out without actual data or having a carb guru physically there with you. Hope you get it sorted out.

 

[one2dmax]

Try adjusting the needle some more (towards richer). You can even try adding some choke and see if it helps. That will let you know if it needs more fuel. The choke only adds fuel and doesn't restrict air like what a normal choke does.

Sean

 

[65fury]

Try adjusting the needle some more (towards richer). You can even try adding some choke and see if it helps. That will let you know if it needs more fuel. The choke only adds fuel and doesn't restrict air like what a normal choke does.

Sean

Hey Sean, tried shimming the needle more(1mm washer) but didnt seem to help, actually if i go WOT with vboost open and im under 3k itll studdar thru the 3k-4k range and continue to almost 7k.... im going to pull the shims and see if my studdaring under 4k goes away. Thanks

Jason

 

[65fury]

Good luck man, I fought with mine for quite a while before I got the A/F kit. The A/F gauge is the best thing to do, you will be able to work with actual data rather than trying to guess what is going on. Some of the symptoms seem to be so misleading, there is no way to figure them out without actual data or having a carb guru physically there with you. Hope you get it sorted out.

Yeah i need something to tell me when its rich or lean(besides pulling my plugs) i might pull my carbs again..... and check to see if they got gummed up or something.... since im outa ideas at this point... ive even gone to a stock setup, 150 mains, stock needle, vboost closed i guess thats it for stock since nothing is changed... and still didnt get any results from that grrrr :damn angry:

Jason

 

[65fury]

Okay so the bike didnt seem to run all that much better with the 1mm shims so i pulled them out and went for a ride.... and I think it runs even worse now..... it studders at WOT thru all the low rpms all the way to 7k If im in 3rd and around 2k and i go WOT it just falls on its face and sounds like its running on 2 cylinders until 7k where it wakes up and goes! But if i close the vboost it runs just a hair better.

When i pulled my plugs to see what color they were... they didnt really have a color... kinda a gray color....... no tan or white. I just dont understand.......

 

[ncdoc0623414]

did you ever figure this bike out or did you just give up

 

[65fury]

Well Ragingman has my carbs right now and is giving them a super cleaning, then putting all stock parts and jets and such back in them. Then when i get them back ill see if my issue goes away... but before this i still havnt been able to pin point the issue. I believe an A/F gauge is on my list if it still doesnt run right, i gotta figure out if im leaning out or getting rich and where its happening. Ill post my results once its running again.

Jason

 

[ncdoc0623414]

ok i was just wondering cause it sounded like a horror story and i had my carbs apart rejetting and rebuilding them

 

[Rhoy Carter]

Have you checked the vboost sensor ?

 

[65fury]

hahahaha well it sorta has been a horror story cause it hasnt run right since i took the carbs apart. :damn angry: but im really hoping the cleaning that ragingman is giving them is gunna do wonders.

hey Rhoy, well vboost control went on the fritz a while back so i removed it and installed a switch in its place, i can open close and partly open it whenever i want.

Jason

 

[jwood]

hey Rhoy, well vboost control went on the fritz a while back so i removed it and installed a switch in its place, i can open close and partly open it whenever i want.

Jason

How was this done? I am looking to do the same thing...


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[PATMAX]

I'm the smart *** with the dumb *** comment I habitually repeat on this Forum. "Get another set of Known condition carbs". I've been in your situation and early on before this Forum) I spent countless hours cleaning and changing stuff trying to get "new like" running power.
Morley Carb exchange is an awesome option and reasonably priced. DannyMax would probably do a tear down/ cleaning/ inspection for reasonable too. Everyone has a different frustration level and there is no better way to learn and understand your carbs than to be going through what you are.
Mike already mentioned it but 4/2/1 exhaust with stock air box? Pod filters, air correctors, bigger mains and drilled slides are all a part of a stage 7 and a better match to that exhaust. Heck, I might have suggested going backwards to a stock exhaust to see what happens in your case but why go backward when you can go forward right?!
Lastly , 4 k miles! I'm impressed. I wish I could find the time to do a cross country trip. Hope you took plenty of pictures!

 

[sdt354]

Nothing like it Patrick. A spare set of fresh carbs. ready to go on is an option I finally fullfiled. Next is a spare complete engine read to install. I have my eye on a nice 1300 Venture engine with 16k. Vmax heads and matched manifolds are almost ready to make it what I want. 135 hp is my goal. Too bad shipping a motor is so expensive.