mid throttle burble

Has anyone experienced a mid throttle burble. It only happens at mid throttle and in mid RPMs usually without much load on the engine, like when running down the road. The rest of the time the bike is great, starts easy and pull all the way through with no problem. I am assuming this is some kinda of jetting problem but everywhere else it runs so good.

I also tried yz timing without changing any jetting and the bike would start missing and popping by about 5000 RPM. Not wanting to go through rejeting the whole damn thing I just switched it back to WR timing, I have been happy there anyways. Before anyone asks, I have already double checked the timing to make sure it is correct.

have you cut the gray wire? if not do a search and read all about it. if i remember right the gray wire affects the mid range and all the jetting in the world wont get rid of it.

:) good luck kevin

I had the same problem running stock jetting on a WR426. Cutting the grey wire didn't affect the sputter, but changing the needle clip position from 4 to 3 made a big difference. I also noticed a big change tossing the stock air filter and going with the UNI filter.


Thanks for responding so quickly. I have already cut the grey wire and I am running UNI filter already. I have also played with the needle and the 3rd clip is the only one it will even run on. I have a race coming up this weekend and I am hoping to have it worked out by then.

try clip 2 in that case! you usually find that if it's a splutter on one position, dropping the needle cures it. but for ultimate running it often takes two drops.

if your needle has to come down that much it's often because the MJ is too big.


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