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1980 KZ750 engine not siezed but hard to turn over
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Hi all -- I have a 1980 Kawasaki KZ750 G1, the LTD twin model. 14,000
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Ouch! Looks nasty.. the kind of thing we all hope will never happen!
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miles on the clock.
I rode the bike about 80 miles on the highway and when I pulled into the
parking lot, the back tire locked up and and the engine died. Now when I
try to start the bike, it turns over, but very slowly and sounds very weak.
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Jammed up starter clutch? It's probably a ramp and roller centrifugal
over-running clutch.
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The bike has a kickstarter too, and its almost impossible to turn it
over even with my entire body weight. Here's what i've deduced:
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If the starter clutch is jammed, you're trying to backdrive the starter
when you kick the level. The starter doesn't like to be backdriven.
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-Not the gearbox, or anything rearward of the gearbox, as it kicks over
easily when the clutch is pulled in.
-Not stuck valves, as I pulled the plugs on both cylinders and tried
again; still turned over slowly but I could see the intake and exhaust
valves moving.
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Looking at the starter parts diagram, I get the impression that you
cannot kickstart your engine while the transmission is in gear with the
clutch lever pulled in.
Is that true? Do you have to find neutral to kickstart the engine?
The design looks like the older style Yamahas of the mid-1960's that
had a ratcheting device that engaged with first gear to start the
engine.
Later designs were called "primary kick starting", because I could
quickly start the engine by pulling the clutch lever and kicking. I
didn't have to find neutral before kick starting if i stalled the
engine at a stop light.
Primary kickstarting wasn't without its problems though. It meant that
there had to be an idler gear that was mounted on the end of the
transmission countershaft.
Yamaha went through about three designs before they came up with a
solid bronze idler gear that could survive sitting stationary on the
end of the spinning countershaft...
I had to split a steel idler gear that seized onto the countershaft
with a cold chisel before I could split the crankcases to replace the
ruined countershaft...
Your motorbike doesn't seem to have an idler gear, as it has a primary
chain going to the clutch...
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Yeah, you're correct in your assumption...if I try to kick it while
pulling in the clutch, the kicker will just freespin and do nothing.
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I would tend to suspect the starter clutch screwing up or the electric
starter then.
Another possibility might be some problem with the chain-driven
counterbalancers.
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-Not a siezed piston, as I can see the piston move when I try and crank it.
Any ideas? I'm guessing its something on the bottom end of the engine.
Thanks all
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