Piston Height

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Re: Piston Height

Postby SPRIDDLER » Wed Apr 22, 2020 7:59 am

Hmm, since the difference in height is about 3/16" it's obviously not a few thou of carbon build-up so I'd take the heads off to check.
I poke badgers with spoons.

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Re: Piston Height

Postby ajscomboman » Wed Apr 22, 2020 8:05 am

3/16 is approx the difference between 8.5:1 and 10.25:1 so it's all pointing towards mismatched pistons. Head off is the only way forward I guess.

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Re: Piston Height

Postby alanengineer » Wed Apr 22, 2020 9:08 am

If you have never taken a head off a bike the job sounds a big one. In reality, its staightforward and may only need either new head gaskets or what you have annealing. Its an ideal lockdown job

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Re: Piston Height

Postby dave16mct » Wed Apr 22, 2020 9:11 am

Just what I was thinking, get em off!!
Dave

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Re: Piston Height

Postby MacL » Sun May 03, 2020 4:15 pm

Hello everyone hope all are keeping well. A bit of lateral thinking before taking heads off to confirm suspicions - if LH piston is higher the compression will be higher. So "e" mailed my next door nieghbour { remember we are social distancing} fellow "jampotter"club member Chris Winiecki . "Have you got a cylinder compression tester?" Next day a test kit appeared on the seat of my G12 -- he keeps his Honda in my garage. Soon fitted and machine kicked over. The gauge registered 27Psi for RH piston [the low one] and 48Psi for the LH. SOooo Doubts confirmed. Will be interesting when heads come off. Not just yet though. Will let you know. Mike.

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Re: Piston Height

Postby MacL » Sun May 03, 2020 4:25 pm

I think I might have been headed for membership of Les Ward's Piston Destruction Club or my third
broken crank.

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