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i have 1997 storm 800 i bought a 1994 vmax 600 for my wife it was having some troubles so i bought a compresion tester .it work out well for my wife sled so for fun i tested my sled my sled has 2000 miles on it this sled starts first pull every time but when i tested it it only had 120 psi per piston i called the local dealer they said it should have 140 per piston what should i do this sled runs mint starts mint please help should i run it should rip it down why have i not notice this problem last year riding
 

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I am Spartacus
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Anything under 120 is considered "lower" compression, and will cause hard starting, plug fouling, etc. Under 100, there's a definite problem....I wouldn't worry too much unless it becomes a real problem to start, etc.
 

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If it helps my Storm is between 125-130 on each cyclinder and starts very easy. One thread I was reading cliamed that the '96 Storm can be better with more compression and stated they were lower compression engines out of the factory. I got a performance tip that the 800 responds very well to shaving the heads and boosting compression. I do not know how true this all is but it is worth investigating. Good luck
 

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Did you do the compression check with the throttle open?
General Maint. would say put a set of rings in to freshen it up.
I'd wait till summer though if it's running good.
 

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i had a 96 storm 800 i shaved the heads jetted and pipped it made a world of difference not sure on the gearing but this thing ran 130 all day long
 

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This might be a dumb question, but I've seen people say they "shaved the heads and raised compression" It seems to me that shaving the heads would lower compression. Am I misunderstanding this or is that not what thay are saying. Just curious:)
 

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I think it means they removed material from the heads, making them "shorter" thus increasing compression because there is less space afterward...:confused:
 

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Yes shaving the heads make the combustion chamber smaller thus increasing the compression ratio. Higher compression has a linear effect to power across the full RPM range of an engine. However, higher compression can be harder on parts and may require higher octane fuels due to detination.
 

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The Snow Man
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Does your compression guage have the release valve on top (near the guage) or on the bottom )where the threads are? To get an accurate reading the valve needs to be on top near the guage otherwise your adding in the volume of the hose as well.

Fess
 

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u don't have to shave down your heads to get higher compression. most of the time u can just put on thinner gaskets. same theory just more conventional. also if u hold it wide open it will give u a higher reading. just trying to make sure its a fair compression test
 
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