Low speed hesitation. Raised needle helped little

Have an 'oo and ride in South LA. Response at just above idle hesitates and throws off balance and timing. Raised need one setting. Raise needle again or rejet, to what size? :)

The needle clip position doesn't affect jetting just off idle much. Too rich of a pilot circuit can cause this though. Are you sure your pilot jet is correct and fuel screw is properly adjusted? Adjust your fuel screw in until you have a slight popping on deceleration then back out about a 1/4 turn.

If that doesn't help or you are already adjusted well, I would guess you are a good candidate for the the BK mod. Visit motoman393's web site for instructions (click here).


Steve T

[ February 03, 2002: Message edited by: skthom2320 ]

[ February 03, 2002: Message edited by: skthom2320 ]

Yes, first try to adjust the pilot screw. And post your jetting specs, this will make it lot easier to help you setting the carb.

good luck.



he'll need to do the taff mod as he has a mk 1 carb.

the needle should only be adjusted at the clip if you're setting the bike up for fourth gear roll-on. to adjust the needle for such low revs is wrong. as said by others.

the PS is the right place to start, as said, turn it in and in a bit more until it improves it. if it doesn't you need a smaller PJ.

oddly enough dropping the needle two clips is a way of finding out if you need a smaller pilot jet. if it works then you do indeed need a smaller PJ.


When I did the BK mod on mine, I noticed that there is already a "boss" on the carb where you need to drill, which gives it the appearance that it is meant to be done. There is also a cutout on the linkage cover as well. I made my own 'kouba-like' T-handle for the adjustment screw with a slotted 6-32x1" screw and a piece of cotter pin.(one half of it) I just epoxied them together and used a spring for tension to keep it adjusted correctly. This made for a vast improvement.


The BK mod will work on ’00 and newer model Yamaha carbs. The pump rod is enlcosed starting in ’00 so the Taffy/Block Connector mod will not work.

Other than that, what Taffy said.

[ February 04, 2002: Message edited by: Hayseed ]

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