Vintage Dirt Bike Q & A

Mr250-not sure if previous owner has carb jetted correct.Can someone tell me the jet sizes, including the 2 small jets, 1 in bowl, one in intake end of carb, and idle and main.Guess its possible he has drilled out also.Or can someone tell me a site where i can find these?Can i find the oem carb # somewhere? Not even sure its right carb>> My manual is not good. Float set at 20MM?Any help is appreciated, before i set fire to it.

Don't set fire to it just yet , I need to find my parts book and I'll get back to you,Gary

MR250 jetting can be a pain. The MR250 was a bit overcarberated for an enduro bike with the stock keihin 34mm. They tend to be jetted fat(rich) and can run much better when leaned out. The stock pilot jet should be 48 the stock main jet a 110. Some of the MR250s I have worked on had a 55 pilot which is correct for the CR250 but not the MR250. Pilot jets are very hard to find but the main jets are the same as current bikes like KTMs which used Keihins with the same type of main jets. I run the clip at the top (leanest) or one down from the top. I looked through old carbs at a cycle parts yard to find a 48 pilot. They are not available from Honda anymore. I also found a 105 main works well here in AZ at 1200 feet. Hope that helps a little.