help please...xt350 not running right

so i just rebuilt my xt350 motor and carb the motor is all stock, the carb has xt600 jets and a shim on the needle- 1 #4 washer both carbs are syncronized to open at the same time to, i am running an irridium spark plug, and cut a 1 inch by 6inch hole in the air box cover the exhaust is stock and so is the air filter i do have a uni filter on order. 


so the problem i am having is when i fire the bike up it does great on the choke but the second i push it in and roll the throttle a tiny bit it runs really rough if i dont tuch the throttle it is fine and if i give it a hand full it is able to power through and runs well in the higer rpms just cant seem to figure out why tis huge stumble at low rpms.....also my fuel mix screw is out 2.5 turns


so not sure if the airfilter will fix this whe it comes in or do i need to adjust the fuel mixture screw more .....any feed back would be greatly appreceated

I'd wait 'til you get a filter in the box . If you try to tune it now , you'll have to do all over again when install a filter .

i do have the stock one in it should i still wait or will that be fine

They should be similar , but the new filter will likely allow a bit more air .


Does the motor idle OK without the choke ? And , if so , at what RPM ?

It does idle ok with out choke once warmed up my tack isn't very accurate though it says like 1800-1900 I think

Maybe a bit rich coming off idle . I'm not sure the needle shims are needed with the larger jets . You might try removing them .

Would adjusting the fuel screw help with that... turning it in?

Would adjusting the fuel screw help with that... turning it in?


Not likely as the motor idles fine off choke . The pilot screw adjusts the amount of fuel during the idle stage . You're having trouble just after idle which is mostly controlled by the needle taper and position .

The different stages of acceleration do overlap a little , but not so much that you can adjust a big stumble out from the next stage . The idea is to have a gradually smooth fuel delivery throughout that matches the amount of air intake to the point of having the correct mixture .

once again pd350 you were right it runs beautifully i removed the shim and it started first kick and pured like a kitten didnt even need choke now it starts first kick everytime, idles nice and low and revs clean at all rps next test is to do it under load but i have way to much snow to test that right now so i will have to let it be for now. 



you really are the xt350 know i tall :applause::prof::applause:

Good you got it running nicely . :cool:

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