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Bad Compresson

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I just got done rebuilding my bike, i have a 13.5-1 hi comp piston, with a 04 gasket, i have a mega cycle cam, wmr racing valve springs, pretty much everything is new except the valves and seats! well I notice that after riding my bike for around 3 hours of hard break in, the bike lost a lot of compresson( i only noticed this when i would start the bike, because it was very easy to kick over). so i checked all my valve clearnces and the intakes are at .06 and exhaust at .08. now I no it is not anything to do with the piston, because if i turn the motor over with no cam shaft(which means the valves don't move at all and are fully seated) the bike has hella compresson, i mean alot! So i don't know what it can be, can it be the auto decompressor, i am really out of ideas on what it can be, any help would be great! also can i lap the stock valves?

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NO DO NOT LAP STOCK VALVES.

Get a leak down tester and do a leak down test...

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I just got done rebuilding my bike, i have a 13.5-1 hi comp piston, with a 04 gasket, i have a mega cycle cam, wmr racing valve springs, pretty much everything is new except the valves and seats! well I notice that after riding my bike for around 3 hours of hard break in, the bike lost a lot of compresson( i only noticed this when i would start the bike, because it was very easy to kick over). so i checked all my valve clearnces and the intakes are at .06 and exhaust at .08. now I no it is not anything to do with the piston, because if i turn the motor over with no cam shaft(which means the valves don't move at all and are fully seated) the bike has hella compresson, i mean alot! So i don't know what it can be, can it be the auto decompressor, i am really out of ideas on what it can be, any help would be great! also can i lap the stock valves?

did the bike get any slower from what you noticed? yea i have work during weekend so i have to finish my top end monday if not tuesday.

i have acually seen another post about someone doing their top end and "not being as fast" so since its my first time topend i hope it doesnt happen to me also. i would like to know if there is any common mistakes that could cause this.

one thing i noticed i got JE piston. and the instructions that came with the pistons were confusing me so i just installed the rings per the service manual.

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IF .06 and .08 mm . you have tight valve. need to adjust.

.08 for the exhauast is minimum, the manual has them set too lose, i keep mine around .09 .10

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