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Piston Suggestions...?

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Wat up,

I am rebuilding my 450 and was wondering which piston to go with? I was thinking the Wiseco or Honda but am not sure of which has a better life? Anyone have any suggestions. I want it to last as long as possible with the best power output if they differ. Also I was wondering what the different compression pistons do? If you use a different compression than stock does it make ur engine work harder or anything. I want very reliable engine components with regular maintanence of course. Let me know what you use and what u think is best. I have a 2002 CRF450 and am putting a new crank and top end in it. I also have KW ss valves and hd springs with less than 4 hours on it I'd say.

Thanks for the info,

Josh #00

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a higher compression piston will raise power and make it slightly harder to kick, also depending how high of a compression ratio you will need race gas. if you really feel the need for more power the high compression piston is the way to go.

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What is the stock compression of the piston? what compression could I go to without race gas? also does the higher compression mean more stress on the engine? :cry:

--Josh

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the stock compression ratio is 12.0 to one. i wouldnt go any higher than 12.5 to one without race gas

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Just put a Honda piston back in it and you'll sleep better at night. That's the piston that Honda (and they are kind of smart) thought would not put too much stress on the motor.

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Comp Ratio on the 02-03 crf is 11:1 or 11.5:1 can't remember which one lots of people on here are putting an 04 CRF piston in which has 12:1 and have good success. I've pit in a Wiseco 12.5:1 in an 03 and I'm happy with it runs stronger now in the bottom end.

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No problems at all. but when I am running in the dunes I've always run U4 because of the high temp's and the amount the bike has to work. U4 is only 92 octane an never had it ping or knock. :cry:

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U4 is only 92? Then why not go to Sunoco and get 94 Pump Gas. Is there a difference between the U4 and pump?

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Any one else have any piston suggestions??

Didn't read the entire thread, but if you are going after higher compression than stock, J&E offers a nice part, as well as Wiseco's 13:1 piston. Stock is a great part too if you just want to freshen up a tired engine. Cheap too!

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i would go with the 04 piston--its cheaper than the 02, has higher compression ratio, and is lighter than the 02 (revs quicker). I put one in my friends 02 and the difference off the bottom was amazing. all the parts (rings, pin, clips) are the same. :cry:

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You would probably get more horser power out of a properly jetted 13.1-1 motor on race fuel.

You'd get more power out of lower octane fuel with a lower compression ratio because you'd be able to tune it properly and still avoid detonation.

Pump gas is oxygenated depending on where you buy it, the degree or amount of O2 in the fuel and what they use to get it there is the question.

Oxygen isnt octane and octane isnt oxygen. Octane is a specific rating, Oxygen is a chemical.

If yous guys want more info on this Id be happy to keep typing, but I think youre prolly already asleep :cry:

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I may be wrong but my guess is the pump gas is measured in RON and the race gas is measured in MON (i think thats the two versions).

If so 92 Mon is way higher than 92 Ron, something like 104-6 Ron...?

I am sure Shawn or some one will correct this....

Mark

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MON stands for Motor Octane Number. RON stands for Research Octane number.

Its different methods of rating. The Motor Octane is measured at a higher RPM. Its the preferred rating for racing fuels. At the pump the number they give you is an average.

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On my 02 i put in an 04 piston,you get a little more bottom.If i was you i would go with a stock piston ,what ever year you put in.I run on pump gas .

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