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Do you have to replate a cylinder after an overbore?

5135 Views 8 Replies 5 Participants Last post by  99RM250
i have a 99 rm250 i am gonna bore it .030 over and i was wanderin if i need to replate it after i bore it? what exactly is replating? thanks alot!
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If you wanted to sleeve it to .30 over, you would need to have the cylinder bored WAY over, then slide the sleeve in to bring it back down to only .030 over. This much machine work is expensive, and not really a benifit unless you plan to race the machine and tear the motor down weekly.
[quote="99RM250]well i already got the .030 piston ordered so i guess i should have it replated? also is it bad to bore it .030 over? im not racing it...i just wanted some extra power[/quote]

Yup, replate it. No. going .030 over is not bad at all. Some people get carried away and go too far over, but .030 is quite reasonable.
Racers tend to tear a motor down after each weekend or sometimes after each run, so the cast iron sleeves are a good idea: they let you hone and even bore to your heart's content without needing to contantly replate, saving time and money.
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