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crf250x jetting

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I have a 2004 crf250x with a fmf powerbomb and factory 4 silencer and the man i bought it from said he put an r head on it and it tends to bog a little. Does a 160 main and 42 pilot seem good? Also it does not have the airbox mod and I ride almost at sea level.

thanks

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160 is too big without the airbox cut open IMO. you didn't state what needle, which can effect the main sizing , 42 is fine on the pilot. put a #78 o-ring on the pump linkage and you'll kill the bog

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the jetting sounds pretty good. check to make sure your leak jet is a 55. I believe 65 is stock on the leak jet. Does it have the stock cam. They run very good with a 250R cam. If you deside to remove the top of the air box and install the R cam then I would step up to around a 165 main jet. Some people also like to go with a 45 pilot jet over a 42..I personally run a 42 with no problems. The opinions are split on the 45 or 42...Both work good.

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Does the leak jet have another name because i can't find it in my manual? Is there a way to tell between a r and x cam just by looking at it, and does a 155 main sound good without the airbox cut or still go leaner?

thanks

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155 sounds a little big for an uncut air box. Open the air box and 155 is good. I would say around 145 to 150 with out the air box cut would be good. I have only heard it called a leak jet....The part number for the leak jet is 99108-MEB-0550. It is screwed into the float bowl. As far as the cam, with out measuring it, I dont think you can tell the difference.

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