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17cc domes 135psi on fresh topend. too low?


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i just tried another tester. i held the trottle open and it was still about 135. would reeds have anything to do with it?

Yes, your reeds can affect your compression. If they are not sealing, some of the intake charge will be forced back throught the carburetor instead of up into the cylinder.

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Yes, your reeds can affect your compression. If they are not sealing, some of the intake charge will be forced back throught the carburetor instead of up into the cylinder.

 

ok. im wondering if that might be the problem. its the only thing i can think of. both testers read pretty darn close to the same. if thats not it, im not sure what else it could be?

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ok. im wondering if that might be the problem. its the only thing i can think of. both testers read pretty darn close to the same. if thats not it, im not sure what else it could be?

You are kicking it till the needle doesn't move at all? If that's the case and your reeds are ok, then I'm afraid it's something internal.

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Pull your reeds and check them...but to get exactly 135 in each cylinder tells me your reeds would have to be as bad as each other....rare.

 

Do a squish test.

 

Take a piece of solder (I use the resin core) in a shape of an L, stick it down the spark plug hole towards the left or right side of the cylinder (NOT front or back) and using your hand, kick the bike over once.

It will smash the solder, get a micrometer, measure how much the solder is "Squished"...

 

Report back.

 

I use .095 resin core solder...

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Pull your reeds and check them...but to get exactly 135 in each cylinder tells me your reeds would have to be as bad as each other....rare.

 

Do a squish test.

 

Take a piece of solder (I use the resin core) in a shape of an L, stick it down the spark plug hole towards the left or right side of the cylinder (NOT front or back) and using your hand, kick the bike over once.

It will smash the solder, get a micrometer, measure how much the solder is "Squished"...

 

Report back.

 

I use .095 resin core solder...

 

it will be tomorrow before i get a chance to do this. i will let you know when done. what does the squish measure?

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