I know it has been posted quite a few times, and I have searched and cant find it--can someone give me the link that explains exactly what circuits the carb is using in reference to throttle position??

With my needle shimmed (i would guess around .40) bike runs awesome with best top speed--but misses and bucks at about 1/8 to 1/4 throttle. Put smaller shim in needle and buck went away but so did 2 mph top speed. Appreciate any help---by the way, i downized main jet from 155 to 150 and bike seems to run a bit better but still no reaction from dial a jet??? Does anyone think I should downsize main any more or scrap dial a jet and go with bigger main jet??

 

According to DJ:

Idle mixture affects idle to 1/8 throttle.

Pilot jet affect under1/8 to past 1/4.

Needles affect under 1/8 to past 1/2

Mains affect 1/4 to full throttle.


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It isn't supposed to work like you describe.

If your carb is not getting a lot of air sucked through it at higher RPMs, then the needle actually has a lof to do with the top speed because you might not be into the main carb circuit. If your engine could really suck through that carb, then the needle would probably do nothing to your top speed.

You need to mess with the cam and raise your compression.

For now, leave the needle at the optimal for the 1/8 to 1/4. Then adjust mains. I think your mains are way too rich for that dial a jet. Not sure, but looks like it from what you said. OTOH, maybe you should loose the DAJ.

 

First of all, what do your plugs look like after you have run it at wide open throttle for about 200 yards and shut off? They should be a light tan color. The pilot jet controls idle and just above idle speeds. When the needle starts to lift out of the main jet is when mid rpm range is starting to be controled. As the needle lifts higher and higher it gets more fuel through the main jet and just keeps increasing the rpm's and power. When the needle is all the way up, the main jet has all the control of the fuel being delivered to the engine. If you are getting a bog when you jab the throttle, your needle is probably too high. I would not put more than a .020 shim on it. If the dial-a-jet is giving you fits, take it off and start from scratch on the jetting. Remember- the most important thing is that it runs good with no quirks. 2-3 mph more top end is'nt that important over running extremly strong through the rest of the power band. Hope all this helps you.