1976 kz750 twin engine seizing and un seizing

I have a 76 kz 750twin. I am currently have problems with it thinking it wants to lock up. As I am riding it, it will bog down and if I pull the clutch it will instantly die. when it does if I go to kick start it. it is extremely tight but I can get it to start but I have to keep the throttle on to over power the engine sticking. I havetaken the generator cover off to check to see if anything could be stopping it andnothing that I saw. PLEASE HELP

If you have access to a bore sight, you can run the pistons to bdc and take a look at the cylinder walls through the spark plug holes.

Alternatively, take the top end off the motor and inspect the cylinder walls and pistons. If no obvious signs of damage, pull the rest of the motor from the frame, split the cases, and look at the bearings and crank.

I would expect the motor to knock if it was the crank and bearings, so it's probably the pistons and cylinders.

schand_08 wrote: I just had this problem recently. starter clutched locked up and was pulling started. I took the chain and sprocket off. and just kick start every time.

Just saw that post in another thread, and unless you plugged the oil hole in the crank that was under the sprocket, that is probably the cause of your current problem.

If you are talking about removing the "starter" sprocket, then 'Never Mind"

Have you checked the oil? Ed

Possibly slipped cam bearing causing the bind...
Pop the sparkies out...
Remove the valve cover....

Visually inspect for slipped cam bearing....

Have you checked the timing chain adjuster for binding...?

1) w/timing adjuster in, rotate the crankshaft manually (ignition plate, not small bolt, Twin 750 so may be different follow manuals directions)
Don't brute strength turn, she should spin with slight force but nothing drastic...
She bind, hard to turn....?

2) Remove timing adjuster in, rotate the crankshaft manually (ignition plate, not small bolt)
Don't brute strength turn, she should spin with slight force but nothing drastic...
She bind, hard to turn....?

Just me but if it were me, pull the head off and find the route of the problem before she really goes bad....

Check all timing components for breakage/binding. With the head off, the crank should spin easily when pulling the timing chain.... Keep the slack off the chain and and in pulling the chain, spin forward/clockwise towards the front of the engine to see if the pistons are binding.....

If pistons binding, possibly piston ring has jumped it's groove thus binding...

OMR

Is there any indication that the engine has become over-heated when beginning to lock up and bog down?

When cold, does the engine crank and run in a relatively normal manner for a short while before beginning to lock up and bog down?

Has any top end work been recently performed on the engine?

Good Fortune!

I didn't do any performance mods. Just had the carbs rebuilt. I removed the sprocket in the starter only and the chain. I've had my dad helping look and he knows a little bit about bikes. We couldn't think of anything. I'm not so sure it actually seizing. It could be dieing and just still running due to momentum.

schand_08 wrote: ...76 kz 750twin...it is extremely tight but I can get it to start but I have to keep the throttle on to over power the engine sticking....

When the engine is stone cold, does it kick over normally, same as a healthy engine, without seeming excessively tight?

Or does the engine always seem excessively tight -- cold or warm or hot -- regardless of its temperature?

In other words, does the excessive engine tightness occur only at normal or above normal operating temperatures?

Good Fortune!

OMR, the Kawasaki KZ twins and small fours don't have separate cam bearings, the cams ride directly on the aluminum.

Need more info, as requested by others.

Kinked fuel hose? Gas Cap vent plugged? The reason I ask if you are having mechanical problems I would think there would be some engine noise involved.

Old Man Rock wrote: Possibly slipped cam bearing causing the bind...
Pop the sparkies out...
Remove the valve cover....

My 79 KZ750 twin does not have any cam bearings.

Starter clutch OK?