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compression check problems


GEARMADE

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here it is last year i ported my cylnders did not need a rebuild so honded it lighty an put in some vitos ss pistons put it back together wow what a difference have mabey put on 10h since starts first kick and is fast as hell just for kicks did a compression check with a new tester warmed it up ,full throtle 1 side had 50psi and the other had 60psi this has to be a bad reading the bike should not even run any words of wisdom

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here it is last year i ported my cylnders did not need a rebuild so honded it lighty an put in some vitos ss pistons put it back together wow what a difference have mabey put on 10h since starts first kick and is fast as hell just for kicks did a compression check with a new tester warmed it up ,full throtle 1 side had 50psi and the other had 60psi this has to be a bad reading the bike should not even run any words of wisdom

 

When you did the compression test do you only kick it once, because when I kicked mine once it showed 50 psi on both sides, also did you hold the throttle wide open? Kick it until the psi dont go up anymore.

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When you did the compression test do you only kick it once, because when I kicked mine once it showed 50 psi on both sides, also did you hold the throttle wide open? Kick it until the psi dont go up anymore.

 

Very, Very good point. It normally takes a good 10 to 15 rapid kicks to get the reading.

You either tested wrong, or the tester is garbage...unless you're 10,000 feet above sea level...:)

 

You should probably be around 130PSI or so...21cc will raise the compression, and porting may lower it just a tad...

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If you kicked it until the needle stops going, the tester is bad, period.

 

Keep in mind, if the threaded part of the tester is not as long as your spark plug threads, you'll be a few pounds low, too. That's head volume that would normally be dispaced when a plug is in there...

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here it is last year i ported my cylnders did not need a rebuild so honded it lighty an put in some vitos ss pistons put it back together wow what a difference have mabey put on 10h since starts first kick and is fast as hell just for kicks did a compression check with a new tester warmed it up ,full throtle 1 side had 50psi and the other had 60psi this has to be a bad reading the bike should not even run any words of wisdom

 

The advise you are getting is good. Even a stock shee will have around 125 psi close to sea level. If the exhaust port height is reduced by about 2mm, it will only reduce the compression by less that 10 psi. Are you sure the compression gauge is valid?

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I think the lowest we were EVER able to pull-start a banshee at and actually ride it was around 75-80lbs in each cylinder. That was at 8800ft with stock head and it had a dead top end. If you pulled it and could get it to fire up it would run though. Just no power at all. LOL

 

Try a different tester!!

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