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Jetting for an 05 CRF250R (White Bros Aluminum Pro)

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What do you guys suggest for jetting for the Aluminum Pro? I seem to have a slight bog right at the blurp of the throttle. It still has the bog regardless if the fuel air adjustment screw is all the way in or out... Im trying to sell the bike to buy some parts for my 450.

Thanks,

Alan

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I would be interested in this as well. I have an '05 with an MX4 pipe and just rebuilt the engine. My altitude is sea level and winter temps are 75F days. Summer 95-110F days <-- I don't ride much in summer!!! LOL!! If we do, it's early in the morning!!

Is relative humidity a large factor in considering jetting?? If so, our RH in winter is 10 - 15%, but in summer runs all the way from 60% to 85%.

Edited by Curlytop

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The jetting should be the same unless you were really close to lean or rich on the stock pipe. The pipe doesn't effect the jetting very much at all. It usually takes a 1/4 turn one way or the other on your air/fuel mixture screw.

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The jetting should be the same unless you were really close to lean or rich on the stock pipe. The pipe doesn't effect the jetting very much at all. It usually takes a 1/4 turn one way or the other on your air/fuel mixture screw.

See heres the thing. Ive had the pipe on it for a while and it ran great. I had a guy once a while back rebuild the carb. And now it runs like crap... So I rebuilt it thinking maybe the accelerator pump still had gunk in it ect and it was clean as a whistle. Only thing I can think of is he changed the jetting? I dont know why he would, But ever since he worked on the bike it ran horrible. What is the stock jetting so I can get some pieces and replace the jets that are in there? Thanks!

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05-09

42 pilot

172 main

Stock leak jet is a 70, but needs to be changed to a 40 or 45,

Needle in the 3rd or 4th position.

Of course, the temperature and altitude is going to effect the jetting. This is just a benchmark to start. It's usually pretty close and the only adjustment you need to make is the air/fuel screw.

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