Jetting help needed for YZ426!

CJG

Member
Nov 24, 2001
221
0
Need jetting help for YZ426F!
I just put an FMF Power Core IV Q silencer on my 426, and I'm having a problem with the engine bogging down at less than 1/4 throttle. I changed to a 168 main(stock162) like FMF recommends but the poor low RPM performance persists. I also tried both a 38 and a 45 pilot(stock 42), changed the clip to the 5th notch on the needle, and tried adjusting the fuel screw with every combo and I just can't get the low-end fixed. Ive tried nearly every combination of the above to no avail. Does anyone have any experience with this bike/silencer combo? What jetting worked for you? Any gear heads out there have any ideas?

Thanks alot!
 
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