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I have idle problem , and hi speed problems ,   idlei is too high ,  when i back off speed screw it dies .  If i open idle mixture screw it will only affect idle untill i get to 2 turns out then nothing .  Also engine stumbles till mid range then takes off ..  I know it needs a bigger hi speed jet .  Now has 110 , going to 115 .  Should I go with a slightly bigger pilot jet ?  

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Posted (edited)

Hopefully it's as simple as a partially blocked pilot jet but 

idling too high and the air screw having little to no effect are signs of an air leak.

also if the jetting was fine before and all of a sudden it feels lean / could use a larger main jet.

 

Don't ride the bike until it's been confirmed/resolved.

 

Check/replace the pilot jet and ideally perform a crankcase leakdown test,

but a basic test is with the engine running, spray parts cleaner around the intake boot, and behind the flywheel (at the LH crank seal)

If the rpms climb up, you've found the air leak.

Edited by mlatour

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Not a dirty carb , or jets .. not an air leak .. engine just completly rebuilt , all new gaskets and seals .  Chasing jetting .  125 stock main too rich .  110  too lean  .  Going with  115 .      Don't  know what is pilot .  Just feeling out possibilities ... going with next size pilot .  

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Where do you live? I’m in the greater Seattle are at 500’ with 46 pilot and a 148 main and it runs perfect to about 4000’

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Previous to the rebuild, was this engine running good with the same jetting specs?

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115 jet runs fine ,  now,  after a throttle up through the gears ,  after backing off ,  it hesitates to get back to throttle  .  Have to wait for recovery ..maybe a second or two ...  Idea's   ???

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17 hours ago, bweighmaster said:

115 jet runs fine ,  now,  after a throttle up through the gears ,  after backing off ,  it hesitates to get back to throttle  .  Have to wait for recovery ..maybe a second or two ...  Idea's   ???

Lower clip one position on needle to richen it. Faster recovery from idle. 

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Yes , of course .  Seen that before on my race car ,  Chief changed whole setup , took 4 races to get back to square one ..    didn't keep notes ,  or job after that ...

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