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05 crf 250r with 270 kit.... jetting ???'s

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I just put a thumper racing 270 kit on my daughters 05 crf250r. I started out with a 42 pilot and a 185 main, she made several laps and complained of a sputter at full throttle, I rode the bike and it was there, I dropped the jet to a 180 and she made several laps and said it was much better. Saturday at the races she was complaining of a popping or hesitation from a steady 3/4 throttle to a full throttle. I never heard the pop or any thing but she's the one sailing this thing threw the air. We will be heading out to the track tomorrow for a few hours ridding any suggestions what to look for if the bike has this problem. It has a DrD full race pipe and a twin air screen eliminator filter kit. Any suggestions would be appreciated. jetting

One note: I does seem to come on the rev box a lot faster now.

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did she say it seemed to get worse as it got hotter?

my experience tends to tell it me its still rich on the main jet,however every motor reacts differently.

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Yes, she did complain it was worse at the end of the motos.

It was running a 178 main with the stock Cly, is it possible that it would need the same or smaller main with the big bore?

Can I change that with a needle if it's a small change.

I am going to pay close attention tonight to make sure she's not coming on the rev box and thinking thats the pop or bog.

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Ok, if thats the case what can I look for in a lean condition?

Thanks for all the info :applause:

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we do a lot of larger cc engines around here and we are running 162 to 168 in the heat.......temps of 85 degrees and up.....below 85 degrees stay in the 168 to 175 range.... and forget pump gas you will detonate the rings out of this thing on pump gas.stay with 100 plus octane fuels.

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I'm running 110 sunoco fuel, the 162 seems way to lean, but i did have 250r one time that would only run with a 142 main. Another thing is it's taking several more kicks to start than it did.

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