Doing Compression reading wrong?

1982 KZ750 Twin CSR All Stock

I borrowed a compression gauge from Autozone, and hooked it up to my right cylinder kicked it over a couple of times and got 60 PSI. Went over to the other cylinder, and also got around 60 PSI.

I than dedicated my time to figuring out why the starter wouldn't work, and I was able to hook up the wires directly and get the starter to spin. My battery was low because I was getting a weak turn over, but this time my PSI went up to 90.
The engine was cold, I had the opposite spark plug in the engine.

Could it be I'm not generating enough power using the kick starter to get an accurate reading?

Would a low battery also cause these sypmtoms since the engine was BEARLY cranking over?


What would cause the starter to just spin, after a couple minutes of cranking, the starter stopped cranking the engine, but I could still hear the starter working, but it was only winding/spinning.


Thanks in Advance!

The bike should be warmed up first to get a correct reading. Choke open, throttle held wide open.

Disconnect the ignition coil, or at least make sure each plug wire is grounded, if not, you can damage the ignition system.

Take out both plugs so it's easier to turn over.

Could be the starter clutch is slipping. but try a better battery before tearing it apart.

loudhvx wrote: The bike should be warmed up first to get a correct reading. Choke open, throttle held wide open.

Disconnect the ignition coil, or at least make sure each plug wire is grounded, if not, you can damage the ignition system.

Take out both plugs so it's easier to turn over.

Could be the starter clutch is slipping. but try a better battery before tearing it apart.

I Did have throttle full open a couple of readings, I never had the choke on, and the bike was cold.

What do you mean by ground the plug?

Yes the battery is brand new, but it already died because of all the troubleshooting I've been doing, since the light stays on when igntion is on. The starter started spinning when the battery got really really low.

USNavy_Perez wrote: [
What do you mean by ground the plug?

The path for spark goes from the coil to the first spark plug to the engine then to the other spark plug then back to the coil. If you interrupt this path, you can damage the coil or the igniter.

When you take out the plugs, connect them to the plug wires and lay them somewhere so the metal part of the spark plug is touching some metal on the engine. This will ensure the path is still complete.

Actually, the metal parts of both plugs can simply be in contact with each other in order to complete the path. The engine does not need to be in the path, but it is often the easiest way of keeping the path complete. You can just rubberband the threaded parts of the plugs to each other to keep them in contact.

Okay I'll definitely give that a try.

USNavy_Perez wrote: 1982 KZ750 Twin CSR All Stock

What would cause the starter to just spin, after a couple minutes of cranking, the starter stopped cranking the engine, but I could still hear the starter working, but it was only winding/spinning.

Thanks in Advance!

It's a 750 twin with two big pistons that love to eat starter clutches.

I think Z1 Enterprises sells a starter clutch repair kit for the 750 twins, and you don't have to split the cases to fix it.

But replace/charge the battery first.