TOPIC:

I bought a '76 kz900 this past winter, knowing it had this issue, and am now trying to get it running and figure out why it's locking up.

With a fresh battery it spins over quick, to me maybe quicker than it should, and sometimes it will just stop dead in its tracks. Move the bike a little and it comes out of it. Sometimes it will spin over nicely for 30-40 seconds, others within a few seconds. Anyone have any ideas? I really don't want to split the cases if I don't have to, but I'm not going to ride it with a engine that locks up randomly obviously.

Thanks, rusted

Not understanding the symptoms.

Do you mean sometimes it stops while you are cranking with the starter?

Or does it stop dead when running?

Does it work with the kick starter?

I have not had the bike running yet, it stops when I'm using the starter. When I first got the bike, you couldn't even move the kicker. I haven't tried the kicker now since I got the starter to turn over.

Have you tried pulling the plugs and letting it sit with some oil/atf in the cylinders?
Try cranking it with no plugs using the kick starter after letting the oil/atf sit in cylinders for a while.

I have not. I'm not sure if its in the cylinders or if its a issue in the trans/clutch/kickstarter. I just think that being it spins over nice and fast and the motor makes many revolutions before it happens and once you move the bike a little it will soon over freely again, that it's not a cylinder issue? Maybe I'm wrong, I'm by no means an expert with bikes, most of my knowledge is diesel related.

I'm not opposed to doing that, but I just want to cover my bases. I'm not trying to come off like a ass so please don't take it that way. If thats something that you really think it is, by all means I'll give it a whirl.

Pull the sparkplugs, transmission in neutral, and it should turn over with the kick lever, if not, something isn't correct. Has the engine ever been apart?

Welcome

Just to be clear, it's the starter that locks up? Meaning you press, the start button it spins sometimes and other times it just stops after a few spins OR is it the engine stalling after it is running?

I noted you said it hasn't run yet. And "moving the bike" makes it go away, I don't understand. Could you list your steps and tell us what happens step by step. Sounds like you have a barn find bike with a new battery and that's where it stands.

Where are you located?

Next time you turn it over pull the points cover off and make sure the rotor on end of crank is turning.

I'm sorry my post have been a little vague, iv been trying to type with one contact in and in the process iv sped things up and not been clear.

The starter turns it over just fine, until the engine itself locks up. When I said moving the bike, I meant rocking it back in fourth, although I'm not sure what that does being its in neutral, but it seams to help.

I'm located in South Dakota. I bought the bike from a Harley guy who got the bike as payment for fixing a Harley for a guy. It was kept in a garage and he too knew of the issue, weather he looked into it or not is another story.

I took the points cover off and the cranks turns fine, but is there suppose to be a spark at the actual points? Also, the spark at the plugs is very weak looking and inconsistent. After messing around with it I noticed that it doesn't lock up anymore. I have a dyna 2000 I might put on to try and eliminate the spark issue, along with a set of 34mm flat slides so I know I have a good set of carbs.

Also, I checked compression with a drop or two of oil and 1-3 were from 100-150, and 4 was just about 200. Maybe I got more oil in 4 than the rest?

I know a lot of this is off topic, but my initial issue seams to be resolving itself, and I figured why make a new thread.

Points can cause all sorts of weirdness. I strongly suggest getting a new set with condensers and starting fresh. It most likely is a timing/points issue. There should be no arcing at the points when they are opening. Arcing is a sign of a bad gap or a bad condenser. Re-gap and set the timing to factory by the book and run it again.