ASK THE MXPERTS: 11 YEARS OF CRF250 PAIN

Dear MXA,
I am the proud owner of a very nice, well-kept and loved 2009 Honda CRF250. It has been a great bike since the day I brought it home, but it has suffered from a dead spot in the powerband that I’ve never been able to cure. I know that I have waited 11 years to seek help from MXA, but I plan to keep this bike for another decade. Help.

You came to the right place, albeit a little late. The Honda CRF250 developed a serious bog problem in 2006 when Honda dropped the 37mm Keihin for a 40mm carb. Honda did not ignore the problem. Honda tried to fix the stock jetting but never hit the sweet spot. Your 2009 CRF250 bogs because the jetting is too lean, which manifests itself as an irritating hesitation when landing from jumps. Additionally, because it is starved for fuel, it can be a very difficult bike to start. You might think that the solution would be to go to a larger main, but the real fix lies in the lesser-known parts of the Keihin carb (pilot, needle and leak jet).

Here are MXA’s recommended 2009 Honda CRF250 jetting specs:
Main: 185
Pilot: 45 (42 stock)
Needle: NNWT (NNSU stock)
Clip position: 3rd from top
Fuel screw: 1-1/4 (2 1/4 stock)
Leak jet: 60 (70 stock)
Notes: The NNWT needle is a 1/2 clip richer than the stock NNSU needle. The Honda part number for the NMWT needle is P/N 16231-KRN-A31.

 

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