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Just picked up an '01 Cr250, Jetting suggestions

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Hey all,

 

Just picked up a nice little 2001 CR250 but the previous owner used to run 20:1 ratio so he had a preset jetting type on the bike. Now, I'm looking to run it at 32:1 ( stock recommendations, plus my other machines run the same mix so it will be way easier for me). I compiled a little table with the current jetting/pro circuit pipe recommendations and reed valves recommendations.

 

Now my question is, instead of buying every jet in the big gap here and try them all, what would you suggest as a starting point? I currently have only the jets that are installed and no extras so I will have to buy all of them.

 

 

jetting chart pic.jpg

Local info:

Ottawa, Ontario, Canada

365ft elevation

will be running in 15-30 degrees Celsius

 

 

Should I start with the lowest of every option such as 390 MJ, 2nd clip, 30 SJ?

 

Now, I understand that jetting is dependent to every bike, I'm simply looking for a good starting point with my two mods( reed valves and expansion chamber/pipe) and I can definitely take it from there.

 

Thanks for the guidance!

Edited by frank2014

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I'd start at 400. Recommended jetting is generally a size or two fat to cover their ass, if stock is 420 I'd be comfortable starting at 400. Then you're probably not going to be running lean and you can go up or down. Or try what you have right now mixed at 32:1 and check your plug and piston wash. If you know how to do jetting you should be able to figure it out man. I'm one of those guys who doesn't like to spend more than I have to, but if you always wanna be making the most power you should be always changing your jets for the temp anyways. I'm pretty sure I'm running a 420 main in my 01 with full fmf and v force reeds but I also keep the same jetting from 5* to 30*C :p
Best of luck, we still got too much damn snow here in Sudbury.
Don

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I ride at 100 to 2000 ft and 45-90 degrees(fah) and have used a 410 main, one size leaner needle-3rd clip, and 32.5 pilot. Has been good for me since new. The Honda owners manual has a very good jetting section and chart. I am one of those who really likes the Mikuni.

Edited by YHGEORGE

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