How to do a Compression Test - Husqvarna SMR510 Supermoto or any other bike with auto decompression

[@ronzibulka5053]

What battery are you guys using on te450 mine all seem weak,how do I know if auto decomp is working(comp too high?)

[@pwnely]

great information thanks explaining! happy to find a video how to do this with this type of bike, you mention filling the sparkplug hole with some oil to see of the pison rings are worn, how much oil do you add? have a great day

[@motardyoda]

sorry mate for the late response been busy at work. so not much oil should be added, I would say 5-10 ml is plenty. Also remember, adding the order will cause the compression to go up, at least any time I add some I get a slight increase in my experience, a small change is expected. Now if you see a 50 psi reading jump to a 65 psi? that would tell me the rings are worn a bunch and time for a top end.

[@davidmucci1014]

So you're using the compression number with auto-decomp engaged as a baseline from what I understand? 50-65psi is obviously very low so I'd assume that's with that exhaust valve under the decomp cam slightly open. (I'm actually amazed these motors start with that low of PSI!) Unfortunately this wouldn't tell you if there's a sealing issue on that exhaust valve when in it's fully closed position (while running with auto-decomp disengaged).

[@alext.9148]

Why did you have to make a 20 minute video for 20 seconds of information