KZ750 won't start, might give up.

There is also timing, which anyone who installed the ignition rotor backward can attest.

You didn't mention the advancer unit, but is there a chance you took it apart to clean? If so, it can be put together backward and the bike won't start even though you will still have spark.

If not already done, would double-check the connections of plug wires from the ignition coils.



Good Fortune!

I think what is getting lost here is that the bike started on the first click of the starter and would run and idle just fine when I first got the engine in. It wasn't until after I put new (larger) jets in the carb that I started experiencing issues.

It started with the new jets, but would pop out of the intake under load. Then the bike eventually died. Then it wouldn't start.

So since I confirmed that I had spark and the fact that I never removed the timing advancer (and it worked not long before), I don't think it's an electrical issue. My guess it is an air fuel issue, but I don't know why. Maybe there is something wrong with the carb that I haven't noticed. It slides, there aren't any tears in the diaphragm, it's clean, bench synced, and I put the DynoJet stage 3 kit in there for the high flow air filter combined with the aftermarket exhaust.

I will try the stage 1 kit next.

Sometimes in the process of removing and re-installing the tank to do carb work, an ignition wire gets loose etc. It's been known to happen in the past, so it might be worth a check.

I just wanted to make sure you didn't touch the advancer. Some people don't always post everything they do so we try to cover the things we've seen in the past.

Would re-assure that valve clearances are within specs AND perform a leak-down test.

A leak-down test injects air pressure through the spark plug hole to pressurize the combustion chamber.

Can perform a poor-man's leak-down test by introducing compressed air into a spark plug hole and listening to where it escapes from the combustion clamber. This may be done at TDC or any other cam positions where both valves are fully closed. Top dead center (TDC) is when the piston is at its highest position. An easy way to tell TDC is by alignment of the T mark with the case mark when viewed through the timing window.

May introduce a spurt of compressed air by using a rubber cone-tip blow gun (rubber air nozzle) held into the spark plug hole. And of course keep holding it in position to keep air from coming back out the spark plug hole while listening for escaping air at other places. The air compressor should not be running while listening because the noise will likely drown out any sound of escaping air. Or just use a portable compressed air tank.

Air heard escaping from exhaust port indicates exhaust valve not fully closing (perhaps too tight clearance or damaged valve or valve seat).

Air heard escaping from carb intake indicates intake valve not fully closing (perhaps too tight clearance or damaged valve or valve seat).

Air heard escaping from crankcase breather indicates loss of compression past rings into crankcase (perhaps worn piston rings or cylinders).

Air heard escaping from head gasket area indicates loss of compression past head gasket (perhaps due to a blown head gasket).

A leaking valve may sometimes be resolved by adjusting the clearance to within specs.

A leaking head gasket may sometimes be resolved by torquing the head fasteners when the engine is stone cold (such as after sitting overnight).

Here's the blow gun I use to inject air into the spark plug hole and then just hold it in position to keep compression in the cylinder while listening for leaks:



Good Fortune!