My first compression test with a motorcycle

So I just performed a compression (dry? no added oil in cylinders) test on my KZ400 d3. And I have a question regarding the procedure. I've pulled both spark plugs and have removed the cutaway slide to my PWK 35 carb. I figured this would be the essentially the same thing as opening the throttle fully. I proceeded to kickstart it several time to get my readings. My question pertains to my first couple attempts at this. I noticed that my readings were higher as I kicked with greater force. I'm not sure if that was just coincidence or not. Since my only other compression test experience is with a modern car, how much force should I be exerting? I just want to make sure I'm not TRYING to give my engine greater compression than is actually true, if that's even possible.

Here are video results of each cylinder:

left/dry ~120 psi

right/dry ~110 psi

compression is produced if stoke of piston is fast or slow.......

the faster the stoke the quicker to max compression.

the slower the stroke the slower to max compression.

either way....you get to max compression.

this is based on a sound engine able to hold compression.

problems that will cause compression bleed off are.

cam timing
valve clearance
valve seat wear
valve wear
bad rings
worn bore
worn piston
blown gasket
cracked head, cylinder or piston
burnt piston

You cannot get true compression readings like that, so do not be at all surprised or the least bit concerned when your compression readings are quite low. It does not indicate a problem other than an inaccurate test.

If you didn't do it - you must thoroughly warm up the engine first. The pistons are tapered toward the top and expand when at full operating temperature; also warming up the engine puts the proper amount of oil on the cylinder walls so you are replicating normal operating conditions. Both of these things help create a better seal between the pistons, rings, and cylinder walls.

You must have a fully charged battery and use the electric starter; kicking it won't pump up the pressure like the starter will.

I suggest you read the procedure in your Kawasaki Service Manual under "CYLINDER BLOCK, PISTONS" in the "MAINTENANCE - ENGINE" section. Ed

650ed wrote: You must have a fully charged battery and use the electric starter; kicking it won't pump up the pressure like the starter will.

Seriously? One more thing to address before I check to see if it's a healthy engine before I go pumping more money into it. Catch-22 I suppose. Oh well. Time to figure out why the electric start doesn't work (kickstart works fine...although a little more effort than I've seen with other bikes on youtube.)