1981 KZ440 won't start, timing problem?

Thanks!!!! I removed the leads and checked directly on the back of the coil and still no reading. definitely a bad coil. I found a used bike parts place here in Portland called Cycleheap that is parting out a running kz440 that had an engine knock. I'm getting the stock factory coil for $37. also a couple of other bits and pieces I need.

Thanks for all your help guys!!!! I'll keep you posted on how it goes...........

Personally, I would greatly hesitate to buy a 34 year old coil.

I would go ahead & get a new coil. When getting used, you might could try a late model 1000P Police bike or maybe a coil from a 2002 or so ZR7 --- at least a coil from one of those wouldn't be so ancient, although 10-15 yrs old is getting there. assuming it has electronic ignition.

Timing Advancer. Also, be sure to clean, check & lubricate the timing advancer. separate the rotor from the body for servicing. make sure the springs are good & that it snaps back after actuating it. I use high temp wheel bearing grease.

Thanks for all the help guys.

I just went out and bought a compression tester from Harbor Freight. I screwed the hose directly into the spark plug hole (didn't use the adapter) and got 90 lbs compression in the right cylinder, and 100 lbs of compression in the left cylinder. Manual says the lowest serviceable limit is 107lbs. It appears my engine needs a rebuild.

The engine was at full operating temperature (hot), and throttle was wide open?

WAIT! The readings you got may be wrong!

In order to properly test the compression the following must be done:

1. The engine MUST be up to the normal operating temperature, This is because the pistons are tapered. When the pistons are at the proper hot temperature they expand near their tops and this enables the rings to seal properly against the cylinder walls.

2. The battery must be fully charged so it turns the engine over quickly.

3. All spark plugs must be removed so the engine turns over quickly.

4. The throttle needs to be held wide open during the test.

If these conditions were not met during the test you performed your readings will be low even though your compression may be perfectly fine. Ed

thanks guys!!! I've been sitting here waiting for somebody who knows what's up to reply.

My battery was fully charged

spark plugs are removed

I DID NOT have the throttle wide open.

The engine doesn't run, so there is no way to get it up to temp before doing the test.

I'm gonna go do another compression test with the throttle wide open and report back.

2nd test results:

engine COLD

battery fully charged

throttle wide open

spark plugs removed

90 psi on right side
100 PSI on left.

What do you guys think?

I think I would try it again with the engine warmed up. If that is not possible then I would do a leak down test. In any case I would certainly do a leak down test before disassembling the engine since that will tell you where you are loosing compression (if you are loosing compression) . Ed

650ed wrote: WAIT! The readings you got may be wrong!

In order to properly test the compression the following must be done:

1. The engine MUST be up to the normal operating temperature, This is because the pistons are tapered. When the pistons are at the proper hot temperature they expand near their tops and this enables the rings to seal properly against the cylinder walls.

2. The battery must be fully charged so it turns the engine over quickly.

3. All spark plugs must be removed so the engine turns over quickly.

4. The throttle needs to be held wide open during the test.

If these conditions were not met during the test you performed your readings will be low even though your compression may be perfectly fine. Ed

+1 I would also check to make sure the head bolts were torqued down to spec.

Benny77 wrote: 2nd test results:

engine COLD

battery fully charged

throttle wide open

spark plugs removed

90 psi on right side
100 PSI on left.

What do you guys think?

Leak down test is best if you can do it.

Another test is to squirt a little oil in the cylinder and repeat the compression test. It the reading comes up significantly (like 20 points or more) it usually means that the rings are not sealing well.

If you do NOT see a big change in compression, it probably means the loss is due to valves not seating well.

If valve clearances are correct, then it probably means you need a valve job.

A leak down test is more informative for sure. However, on an engine that has not run in 8 years, even a leak down test may be misleading since the rings may be stuck and not properly sealing. Surely even 90psi is enough to start with.
Seems to me that it would be best to check valve clearances to be sure none of them are way off, run the engine enough to loosen the rings and then continue testing.