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Dirt Bike Brands - Other
1985 cr 250 top end rebuild...very little power
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[QUOTE="76GMC1500, post: 1187078, member: 73139"] What exactly is your definition of a power valve? To me, a power valve is a "valve" on the exhaust side of a 2-stroke engine that varies something (expansion chamber volume (ATAC), port timing/area (HPP), or whatever(KIPS and the like)) in relation to engine speed in order to maximize the useable power range of an engine. An ATAC valve stuck shut throws off the timing of the expansion chamber so the bike will run fine through the low/mid range, but not have any power on top. It will make the bike feel gutless. Since a top end rebuild was just done and the ATAC valve has to be messed with during the rebuild, it is very likely that it is not operating properly. I would also suggest the reeds be inspected, but if the bike starts fine, I find it unlikely that they are a problem. Wiseco rings are generally cut to spec, but it's always a good idea to double check because too tight of a gap can destroy an engine. [/QUOTE]
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Dirt Bike Discussions By Brand
Dirt Bike Brands - Other
1985 cr 250 top end rebuild...very little power
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