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I"m new to the forum. Picked up a really clean 01 cr250 a few months back and I love it. Was always my dream bike growing up. All my friends are living in the 4 stroke world and I'm a 2 stroker forever! Anyways the bike already came with a boyesen rad valve installed, and I recently put on a fmf gnarly pipe and shorty silencer. Took my carb apart to see where my jetting was at and it's set up as follows:


Main: 430

Pilot: 30

Needle 6BEH1-75

Clip Position: 2nd from top

Not sure on the air fuel i forgot to check


I know there have been countless discussions about tuning the mikuni's on the 01's and correct jetting depends on a lot of variables. My question would be does any have a similar set up as me and what are you running? Also is the JD kit worth while for this bike? I've also just bought individual jets so I'm hesitant to buy the kit if I don't have to. This is my first experience with a 2stroke carb though. Any help or discussion would be greatly appreciated.


Thank you,


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Dan, I don't own a CR250, or anything with a Mikuni anymore, but check this out and use it to help you learn your carb: http://users.conwaycorp.net/virtus/page2/speed/jetting.htm

There is also "Is my two stroke running rich" in the Yamaha two stroke forum stickies. It contains some of the same info, and a bit more.

You can find a starting point for jetting on the FMF website, but it is only a starting point; every bike is different.

I personally wouldn't buy the JD kit, as I feel like you pay $75 for two needles, if you already have the other jets on hand. I'm sure he earned it through R&D, though.

Some people swap the Mikuni carbs on these bikes for a Keihin PWK.

Congrats on the new bike! Welcome to the forum and to the joy of two strokes.

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