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Discussion Starter · #1 ·
Hey all, I want to do a compression test to ensure my piston rings are good, what is a way to temporarily disable the auto decompression on the exhaust cam so that I may get an accurate compression reading? Let me know. Thanks!
 

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Do a leak-down test. Compression testing is almost impossible to do. If you see smoke, consume oil, or have a fair amount of oil flying out of your breather it's probably time to do the top end.
 

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2019 YFZ450R SE
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Do a leak-down test. Compression testing is almost impossible to do. If you see smoke, consume oil, or have a fair amount of oil flying out of your breather it's probably time to do the top end.
How is it almost impossible to do? As far as cars go, you eliminate spark, Fuel, and the spark plug and crank the engine over while at wide open throttle for several rotations to get the initial compression test reading. Then from there you do a wet compression test to determine whether there's a loss of compression in the Rings or The Head. I've never done it on a four wheeler but there has to be a way to apply the same technique on a car to a four-wheeler
 

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Discussion Starter · #4 ·
How is it almost impossible to do? As far as cars go, you eliminate spark, Fuel, and the spark plug and crank the engine over while at wide open throttle for several rotations to get the initial compression test reading. Then from there you do a wet compression test to determine whether there's a loss of compression in the Rings or The Head. I've never done it on a four wheeler but there has to be a way to apply the same technique on a car to a four-wheeler
In the exhaust cam, there is a mechanical mechanism the uses centrifugal force to decompress your bike upon starting it to make it easier on your engine and overall to start. I guess I’ll do a leak down test then
 
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