Starter spins, but won't turn gears when reinstalled.

[Guest]

Hi everyone - I've been rebuilding an 82 GS850GL, but I can't get the starter to turn the gears that turn the flywheel. I removed the starter motor and connected it to a 12v car battery and the starter spins perfectly fine. When reinstalled, I tried the same 12v battery, but it doesn't spin.

I put a wrench to the bolt on the flywheel, and there is good compression and I'm able to turn the flywheel 360 degrees. I believe that means the engine isn't seized, correct?

And ideas? Can a jammed up starter still spin, but have limited power?

Thanks - I'm new to the group, but am glad there is such a great resource for this bike.
Andy

[Steve]

There is an idler gear between the starter and the flywheel. If that was not installed properly, something might have gotten jammed and is preventing it from turning.

Take the spark plugs out, so you don't have to fight compression, then try to turn the flywheel backwards. If anything is jammed, that is when it will show up.

Oh, to positively rule out the engine not being seized, you need to turn the crank at least two full revolutions. Yes, just being able to move the crank will tell you something, but if something is caught in the valvetrain, it might not show up in the first revolution. The cam only spins at half crank speed, so it takes two turns on the crank to turn the cam over once.

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[ajseavers]

There is an idler gear between the starter and the flywheel. If that was not installed properly, something might have gotten jammed and is preventing it from turning.

Take the spark plugs out, so you don't have to fight compression, then try to turn the flywheel backwards. If anything is jammed, that is when it will show up.

Oh, to positively rule out the engine not being seized, you need to turn the crank at least two full revolutions. Yes, just being able to move the crank will tell you something, but if something is caught in the valvetrain, it might not show up in the first revolution. The cam only spins at half crank speed, so it takes two turns on the crank to turn the cam over once.

.

Thanks for the response. I'll look for the idler gear. I'm able to turn the flywheel backwards without taking the spark plugs out, but I'll try that just in case. I'm able to do as many turns on the crank shaft with issue.

[tom203]

So starter motor spins out of motor.. Reinstalled, does it still sound like it spinning, but just isn't turning engine over, or .....?

[geol]

If you can turn the engine over without removing the spark plug (manually turn it over with the nut on crank end under the points cover), you had best get a compression tester gauge and check compression.

[JTGS850GL]

If you can turn the engine over without removing the spark plug (manually turn it over with the nut on crank end under the points cover), you had best get a compression tester gauge and check compression.

No need to check compression. You can easily turn the engine over with the plugs in place. You'll feel each compression stroke but it's not like it's impossible to turn it over.

The original question still needs to be answered. Do you hear the starter motor spin but no engagement or is the starter locked up. Either way, you need to remove the stator cover and see what the starter clutch area looks like. Is the motor engaged into the idler gear? Is the idler gear in position? Is the starter clutch working?