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Discussion Starter #1
my bike is running so good after a rejet and k&n filter.
I've shimmed the needle with two washers from procycle and I have my fuel screw at 2 1/4, but I still get a very annoying hiccup at 3/4 WOT so cruising around.

So using the google carb tuning chart.
ATV Carburetor Jetting Instruction - ATV Technical Articles
The main is to big or to small? its currently a 110 right now from procycle.
 

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.....
The main is to big or to small? its currently a 110 right now from procycle.
This is a pre-2001 TW ?.....with the round slide carb?

Thinking out loud.... Why a 110? The stock main jet for the slide carb is 114. Have you tried the 112 and 114, and 116? With what results?

Just a guess, but I think the 110 is too small.

Have you done the tuning procedure? Or did you take someone's word for what the settings should be?

Did you purchase the ProCycle jet kit? If so, what jets are included?

jb
 

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Discussion Starter #3
This is a pre-2001 TW ?.....with the round slide carb?

Thinking out loud.... Why a 110? The stock main jet for the slide carb is 114. Have you tried the 112 and 114, and 116? With what results?

Just a guess, but I think the 110 is too small.

Have you done the tuning procedure? Or did you take someone's word for what the settings should be?

Did you purchase the ProCycle jet kit? If so, what jets are included?

jb
Awesome a reply!

IM a new owner so lets run down the specs: 1994 round slide, K&N filter replacement and all new carb o-rings with verified no vacuum leaks.
The main jet is a 115 now- these are the jets provided by pro cycle which are not OEM. So I think these jet numbers do not match up to the Teikei numbers, I believe they are Mikuni jets, small round.

The pilot circuit is perfect all off idol and mid range putt power is dialed in.
The plug is currently gaped at .020 and is a golden brown (guessed at gap just wanted to get a close known baseline)
The needle has two washers underneath it, have you noticed the round slide carbs have a little quarter spacer stock? its like a washer with a small tang on it for alignment. Im thinking thats a possible 2 1/2 washers.
whats really throwing me off is the bikes plug is lookin good, but the last quarter of the throttle position and the rpm at the max speed is choppy.
I guess I have never gotten it rich and backed off so I could try bigger jets and another new plug to watch. I just really want to know whats gonna be contributing to the "chop at the top" its not the needle right? its all main jet and.... anyways thanks for any help and any other ideas!
 

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Thanks for the details... important if anyone will be able to help you.

After I posted, I recalled that ProCycle was not using Teikei jets. Since the numbers don't correspond with the Mikunis, ProCycle may be the one to assist you.

A call to them, or a PM to Mr. Bracket (on this forum, their TW specialist) might solve your problem.

Other thoughts.... the 3/4 throttle position is the transition point between the influence of the needle and shims, and the main jet...but since the influence of the needle/shims overlaps that of the main jet, either could be causing the problem.

As I looked at the photo on the ProCycle website, the shims looked thicker than the .01" shims I use...but that may just be the photo.

If no one can provide you with a definitive answer, you will need to do some "trial and error" yourself with the shims and jets.

i tend to agree with you that the main jet is the problem. Trying one size larger or smaller should point you in the right direction.

...another thought...check the fuel level in the float bowl.

Here is a chart that I prefer over the one posted on your link.

it shows that the pilot jet/circuit continues to add fuel throughout the throttle range...which it does.

...and lots of overlap between the parts.



jb
 

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Discussion Starter #5
thanks for the pointers I'll probably shoot a pm over to the guru,
take a shim out and get a setting on float bowl level. I'll be back thanks! Awesome.chart BTW
 

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Discussion Starter #7
sideways

Don't forget to give the http://tw200forum.com/forum/technical-write-ups/591-carb-tuning.html sticky a good read and then follow the procedure to save yourself the guessing games. Clean>Main Jet>Needle>Screw
All of that is very helpfull and just as I suspected im off in left field blind with the procycle jets because the numbers mean absolutely nothing to this carburetor. Back to square one on bike bandit ordering xtparts and hoping they fit. another 50ish dollars FLUSHED!
 

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Hope that helps.
 

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Hope that helps.
If only there was a way to cross reference the Teiki jets against mikuni jets. Good thing there so cheap and available I can try super rich and super lean untill the bike runs right, just a shame I didn't figure it out earlier.
 

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If only there was a way to cross reference the Teiki jets against mikuni jets. Good thing there so cheap and available I can try super rich and super lean untill the bike runs right, just a shame I didn't figure it out earlier.
Did you contact ProCycle?

It seems that if they are going to sell kits with non-factory jets, they should provide a cross reference for the comparable sizes.

jb
 

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Don't forget to give the http://tw200forum.com/forum/technical-write-ups/591-carb-tuning.html sticky a good read and then follow the procedure to save yourself the guessing games. Clean>Main Jet>Needle>Screw
Update to an old post:

I would respectfully disagree, slightly. IMO, you need to get the pilot screw adjusted first.

If the engine doesn't idle properly, you will find it difficult to dial in the main and needle.

The pilot circuit not only meters the fuel during idle, it continues to provide fuel all the way to full throttle, although to a lesser degree than the needle and main jet.

Then the pilot screw should be adjusted again.

You all are welcome to disagree. :)

jb
 

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Update to an old post:

I would respectfully disagree, slightly. IMO, you need to get the pilot screw adjusted first.

If the engine doesn't idle properly, you will find it difficult to dial in the main and needle.

The pilot circuit not only meters the fuel during idle, it continues to provide fuel all the way to full throttle, although to a lesser degree than the needle and main jet.

Then the pilot screw should be adjusted again.

You all are welcome to disagree. :)

jb
This is exactly how Sudco says to tune Mikuni round/flat carbs.
 

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...............................its currently a 110 right now from procycle..........................
If you are satisfied with the way it runs then leave it alone.........

Speaking from my personal experience I say start with a NEW #114 jet. Don't try to make the old one work no matter how good it looks. Get a NEW #114 jet. You will be far ahead in the game if you do.
 

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Hi Tony, this thread is from a year ago.

I doubt that LATW is still around since his post count hasn't increased in all that time.

I updated the thread with a slight difference of opinion with Qwerty's often quoted "carb tuning" advice.

jb
 

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Hi Tony, this thread is from a year ago.

I doubt that LATW is still around since his post count hasn't increased in all that time.

I updated the thread with a slight difference of opinion with Qwerty's often quoted "carb tuning" advice.

jb

Proud of yourself for agreeing with me? Nothing to brag about because what you wrote is no difference at all so knock off the chest pounding. Nobody with two brain cells to rub together is impressed that you have the capability of a cockatiel to reproduce words. I wrote "It is best to give the carb a good rebuild first unless the carb is practically new. You can't tune mechanical problems out of the fuel system." That would include the pilot screw condition and setting. I also wrote "The pilot jet and screw do affect operation at high throttle, but not very much." You have enough good info you've contributed to this site, what the hell is wrong with you that you feel necessary to plagiarize me?

Anyone who really wants to learn to tune a TW carb using the time proven method that actually works go here.
 

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But, he's so warm and cuddly most of the time? :p Maybe he's feeling under the weather? :confused:

pause..

pause..
Naaa, he's just being a dick. Hi Q! :hiding:
 

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I saw no reason to qwerticize jbfla's post is such a spiteful manner, that seemed totally uncalled for.
I think getting the pilot screw setting dialed is very good advice assuming jetting is in the ballpark. It can be an iterative thing to balance the fuel metering circuits.
I plan to apply the wisdom of all your inputs to my bike very soon.
 
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