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707

Big Bore for 426f?

11 posts in this topic

Is there a way to get it to 450cc? or is there any other big bore kits around? thanks.

A 2mm overbore (97mm piston) will get you 444cc which is the practical limit for a bore increase on an OEM cylinder. Displacement beyond that would require a stroke change or a recast cylinder like Athena is building.

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no,the wiseco piston boosts compression not displacement,i have it and i still wont chase down the 450 on a long straight :cry:

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no,the wiseco piston boosts compression not displacement,

You can get a 13.5:1 version of the 97mm Wiseco piston that will bring the displacement to 444 after a rebore/replate of the cylinder. If the rest of the engine is done right it will run with the newer 450s .

Here's a dyno chart of SFO's 444 running stock cams (reindexed) and stock valve sizes. At 52 horsepower on pump gas and 54 on Nutec it can stay with the 450s no problem. :cry:

http://www.four-stroke.com/Dyno_runs/SFO_index.htm

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My buddy has a 450 big bore kit on his.... It has blown up twice, but I'll find out where and what he has done to it.

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