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Hi Compression Piston?

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I am looking for some insight on running a high compression piston in my 05 CRF450. I was thinking probably the Wiseco 12:1 but wanted some feedback first. Also at what point do you have to run race gas? Thanks for the help.

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I am looking for some insight on running a high compression piston in my 05 CRF450. I was thinking probably the Wiseco 12:1 but wanted some feedback first. Also at what point do you have to run race gas? Thanks for the help.

Ive got the 03 450 and have the 12:1 wiseco piston. you can run it on pump gas. and isnt the the stock compression for your bike though. mine came stock with 11.5 but its an 03.

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I'm putting a 13.5:1 JE piston in my 04 CRF450. It doesn't require race gas. Stock compression for the 04 is 12:1 and I think it's 12:1 for the 05 also.

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I am looking for some insight on running a high compression piston in my 05 CRF450. I was thinking probably the Wiseco 12:1 but wanted some feedback first. Also at what point do you have to run race gas? Thanks for the help.

I'm trying to be helpful, not a smart ass, but you will find tons (and tons) of threads on this topic if you use the search button.

I'm in the process of rebuilding my '02 R and have found almost everything I need by searching.

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I'm trying to be helpful, not a smart ass, but you will find tons (and tons) of threads on this topic if you use the search button.

I'm in the process of rebuilding my '02 R and have found almost everything I need by searching.

Maybe he wants some up to date info...lol just teasin. Ive heard you can run pump gas in the 13.5:1 so, just might not last as long.

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I have a big bore 470 with 12.5:1 and have always run pump gas No problems at all. Mine is also a 05

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I'm about to put together a 470 kit with a 13.5:1 JE and RHC 208, valves and springs. How did you like your 470 kit did you notice a good mid range and low end grunt increase?

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I will comment on the JE Hi comp. I have run this piston a full season with the main ring gapped at .010, pump gas and just took my motor down thinking it would be eaten up from railing on her so hard all season in the sand(this is a 05 CRF 250R). The piston is spotless. The ring was in spec. The skirts were perfect barely a mark whatsoever. Measured perfectly. I seriously couldn't beleive it. I honed the cylinder and re-ringed it.:applause:

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My bike does really pull hard down low and keeps pulling thru the middle, it seem to sign off alittle sooner but im dropping a couple teeth on the rear just to see what that will do to top speed. I do alot of desert riding with a bunch of friends that have 450s and mine walks away from them no problem. Its the funnest bike Ive ever riden. Yank your arms out fast.

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My bike does really pull hard down low and keeps pulling thru the middle, it seem to sign off alittle sooner but im dropping a couple teeth on the rear just to see what that will do to top speed. I do alot of desert riding with a bunch of friends that have 450s and mine walks away from them no problem. Its the funnest bike Ive ever riden. Yank your arms out fast.

you may want to try one size up on the main jet. It shouldnt flatten out on top even with the higher compression ratio higher. Its a thumper, not a two stroke.

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