carb take 2

Jonathon Jay annihilator1100 at
Wed May 13 17:16:49 PDT 2009

Ok, now a couple questions. 

I wouln't know a 108 main if it bit me in the ass. Same for this talk of clip and shim.

What I have is what was included in my DJ kit.

As long as I use my stock springs can I make it run well with the DJ supplied parts?


Will I have to remove carbs every time I make adjustments?


Lastly, I am cleaning the carbs too. I very carefully pulled the rubber diaphrams out, they're about the circumfrence of a lime and the needle goes in the middle. There appeared to be some mild adhesive helding them in. When it is time to reinstall, what do I use for adhesive?



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> From: blackgpz at
> To: gpzlist at
> Subject: Re: carb take 2
> Date: Wed, 13 May 2009 20:04:23 -0400
> >>Don't screw around with the pilot screws if it idled right before you 
> >>put the kit in. All the screws do is affect mixture up to about 1200 rpm 
> >>or so.
> This is not correct. The pilot screws affect air:fuel up to about 4000 rpm 
> so it is important to get these right for good part-throttle cruise. You 
> must have the ability to adjust them so remove the plugs covering them as 
> outlined in the jet kit.
> My recommendation FWIW:
> Install 108 main jets (as you have an aftermarket exhaust, particularly the 
> large headpipe SS2r)
> Do not change the pilot jets if you are keeping the stock airbox.
> Set the pilot screws at 2 1/2 turns out from lightly bottomed. Your 
> adjustment range is 1 turn to 4 turns out. 2 1/2 turns out is the middle of 
> the range and a good starting point.
> Drill the slides - be careful.
> Put an e-clip in the second groove from the top of each needle. Put a shim 
> washer on top of that, then put another e-clip in the first groove to retain 
> the shim washer. This clip-shim-clip arrangement duplicates the thickness of 
> the "nailhead" of the stock needle so there will be no up & down play of the 
> needle in the slide when you put the white plastic retainer over it. Make 
> sure none of the "feet" of the white plastic retainer cover the slide lift 
> hole.
> DO NOT install the kit supplied diaphragm springs. Reinstall the stock ones.
> Put it back together and fire it up.
> There are 3 circuits in the carburetor. The main jet is used in the 7000 to 
> redline RPM range, the needle controls the 4000-7000 rpm range and the pilot 
> screw from idle to about 4000 rpm. This is simplified a bit as there is some 
> overlap but for adjustment purposes, these are ranges each have the most 
> effect on.
> Start with the main jet. You must get this one right first. Take it out and 
> run it in the 7000 and up range. I know it's hard because of the speed 
> involved but what you are looking for is good throttle response, it pulls 
> hard and none to maybe a little blue smoke.
> Next is the needle. Again, run it in the 4000-7000 rpm range. Again you are 
> looking for good throttle response, pulls hard and makes a good transition 
> through 7000 rpm.
> Last is the pilot screws. What you are striving for is smooth running at a 
> steady 4000 rpm in second gear. If it runs smooth from the git-go, turn the 
> screws in a half turn at a time until it begins to surge and buck, then back 
> them out a half turn so you have the leanest setting the bike runs smoothly 
> at. If it surges from the start, back the screws out a half turn at a time 
> until it just goes away.
> Everybody's bike is different and some adjustments may need to be made to 
> tune your particular bike. The above is a good starting point.
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