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The rules for the class I run in allow overbore of up to .040" and replacement pistons as long as they are the same shape and weight as stock pistons. Compared to a good re-hone and re-ring rebuild with the stock pistons, could I expect any significant performance gain by going with an overbore of either .020" (max size for Honda pistons) or .040" (custom pistons)? If there is not much of a gain than I'd rather save the money and reuse the stock pistons, as long as they check out ok.
 

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Stay with +.020". Gains with bigger bore on stock sleeves are insignificant, and actually smaller bore could be better because if you bore it too much, sleeves get too thin, they may start to bend slightly, blow head gaskets, leak thru piston rings, engine cooling suffers and sleeves can even crack.
 

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D-series Janitor
Front Engine Dragste
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it is a good idea to check the thickness of the sleeves before boring.

If it is class racing, bigger is better. More cubes and unshrouding the valves, its a win/win situation.
 

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You would gain very little power with a .040 overbore. It would only increase your motor size by 1.6CC.

They allow an overbore so you can run rebuilt motors that have been rebored to true the cylinders.

I would have the block checked and if a hone will bring the cylinders back to spec, go with stock piston size. Spend your money on the head, thats where the power is.:TU:
 

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'89 CRX HF
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unless you have a sick ported head, IM, TB, and cam to back up the overbore, you probably wont notice any difference

one plus is that you have a nice fresh sleeve which would be within the clearance specs of brand new pistons :TU:
 
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