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07 RMZ 250 hesitation at slight throttle opening

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Ive searched these forums and it seems no one has had this problem. First off all its stock jetting, I did try going from a 42 to a 45 pilot with no luck. I' m at sea level and the temp is 80.

I just bought th is bike 3 weeks ago and the first ride I noticed that while riding in any gear at idle and I very slowly roll on the gas at right about 1/8 throttle it hesitates badly and will continue untill I change the throttle opening. Everytime I get on the gas I can feel that moment when I hit that spot. First thing I took the carb apart clean inspected it checked the ap timing. Reassembled it tried to set the pilot screw by setting the idle high and cranked it in all the way and it had no effect at all couldnt even tell I was adjusting anything, which I thought was odd. I then started playing with the ap timing and that didnt help at all.

I forgot the bike is stock except a fmf slip on.

Any help would be great I was at the mx track today its driving me nuts

Thank you.

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Ive searched these forums and it seems no one has had this problem. First off all its stock jetting, I did try going from a 42 to a 45 pilot with no luck. I' m at sea level and the temp is 80.

I just bought th is bike 3 weeks ago and the first ride I noticed that while riding in any gear at idle and I very slowly roll on the gas at right about 1/8 throttle it hesitates badly and will continue untill I change the throttle opening. Everytime I get on the gas I can feel that moment when I hit that spot. First thing I took the carb apart clean inspected it checked the ap timing. Reassembled it tried to set the pilot screw by setting the idle high and cranked it in all the way and it had no effect at all couldnt even tell I was adjusting anything, which I thought was odd. I then started playing with the ap timing and that didnt help at all.

I forgot the bike is stock except a fmf slip on.

Any help would be great I was at the mx track today its driving me nuts

Thank you.

If adjusting the fuel screw has no affect on idle you have one of the following:

- a pilot that is wayyy to big or small (which you don't)

- a passage above the pilot jet that is partially clogged- but then it wouldn't idle well or at all

- a hot start plunger that is leaking or stuck partially open

- a choke plunger that is leaking or stuck partially open

- an air leak that is leaning out the pilot circuit...usually a missing oring on the fuel screw

...but, 1/8 throttle is technically past the pilot jet range an into the needle jet.

I would try moving the needle radically up or down to see if there is an affect.

You should have a NCVS or NCVR needle in there. The emulsion tube the needle drops into can also get a 'wear' spot in it which causes wierd symptoms too.....

Edited by Krannie

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Well I moved the needle up and I still have the same problem. There is a wear spot on the tube like you said. Here is a link to a video I just took. The second pass you can hear it pretty good.

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