CRF's Only Forums

I have a 09 250R and from my understanding it only had 20 hours on it and is stock. I have a low end bog when you blip the throttle, if you go fast enough between movements, the bike will bog, then rev, bog then rev, and if you get right, you can bog it and the bike will cut off. I noticed the AP jet looks as though when you get on and off like that it may be flooding it but I am not a tuning wizard. Here is what I tried:

When i got the bike it was running
Pilot - 42
Main - 178

I tried the following:

Pilot -42
Main - 188

Pilot -45
Main - 188

Pilot -48
Main -188

Pilot -48
Main - 178

Pilot -45
Main -178

Pilot - 42
Main - 178

-Air fuel was 1.50 and 2 out for all scenarios
-AP gap was adjusted so no need for the mod in terms of the wire

None of these combinations worked and the 188 may have been less bogging but it was still evident. My buddies Yamaha is flawless and I know these honda's have this issue but my 06 had it and once I did the AP mod it was great.

Thoughts anyone?

If you increase revs slowly does it run cleanly?
If it runs clean and it is only as a result of opening the throttle quickly then the AP will need work to cover this flat spot.

JD jet kit and the crf fuel screw cured mine...

Consider an R&D Power Pump 2 with adjustable leak jet.

You can't go wrong with the JD jetting kit, best $70 I spent on my 250X. Their customer service is over the top as well. Send them an email describing your altitude, normal riding temps and your bike's setup (exhaust, cam, air filter, and mods) and they will respond with recommended jetting and fuel screw settings.

Dirtdiver73 wrote:You can't go wrong with the JD jetting kit, best $70 I spent on my 250X. Their customer service is over the top as well. Send them an email describing your altitude, normal riding temps and your bike's setup (exhaust, cam, air filter, and mods) and they will respond with recommended jetting and fuel screw settings.

i agree! the instructions included are spot on for 95% of those installing it. if you're one of the 5% and want JD's help he'll reply back quickly with his recommendations. this true whether you buy directly from him or from CRF's Only.

Most obvious things first...make sure the pilot jet is not clogged and the gas isn't bad. Sounds ridiculous but most bog issues are for those reasons. Otherwise, it may be a tuning issue with closed to 1/4 throttle which is fuel screw related. I put JD adjustable fuel screws in all my Hondas that have FCR carbs and it's the best $18 dollars you can spend. Temperature of 10 degrees difference, elevation change, or even humidity will make CRF's bog, stumble, and run differently.