Compression test on removed engine

[Karstan]

Is there a way to run the compression test on an engine that has been removed from the frame? I've tried hooking up the battery and just bumping the starter to do the test that way, but I'm getting readings of zero psi. The engine ran before removal. Also, I've got all the covers off. Will just putting them back on give me what I need? Or does it need fuel?

[Homie]

With the engine removed, you would be better off doing a "leak-down" check. It doesn't require cranking of the engine and it gives you a better indication of the "health" of each cylinder.

[Guest]

Is there a way to run the compression test on an engine that has been removed from the frame? I've tried hooking up the battery and just bumping the starter to do the test that way, but I'm getting readings of zero psi. The engine ran before removal. Also, I've got all the covers off. Will just putting them back on give me what I need? Or does it need fuel?

You need oil in the engine and does it have carbs installed?
You should be getting something though so is the compression tool any good?

[tom203]

[QUOTE=chef1366;1616841
You should be getting something though so is the compression tool any good?[/QUOTE]
Yeah, nothing makes no sense

[Karstan]

Old Skool: Thanks! I'll search the forums for this leak down test.

Chef & Tom: No carbs currently installed. I got a little something on cylinder #1 (about 65 psi) on the first test but I'm not getting anything now. There's a loud pumping sort of sound when I bump the starter, so it certainly sounds like there should be pressure.

[tkent02]

Having the carbs removed makes no difference, it's just like having the throttles open which you would do on a compression check anyway.
Don't just bump the starter, let it crank several revolutions, then read the compression gauge.
Check the easy things first, are the valves adjusted correctly?
If the valves are too tight, there can be no compression.
Likewise if they had been burnt from running too tight, no compression.
Has the engine sat unused forever? If so, sometimes piston rings need to be freed up, although you would expect at least some compression in this case.
Can you give us a little history on this motor?

[Karstan]

tkent: I bought the bike a year and half or so ago. I rode it up through last October, so it was running until then. It's been sitting for the past few months.

[Guest]

Motor running = compression
something is flawed in your compression check. Does it blow your finger off the spark plug hole when turning over the motor?