Symptoms of engine seizure but engine not seized??

[esclarsky]

Hi all,
I am getting quite frustrated with my bike, an old '89. Here are the things:

Without a fully charged battery or proper jump, the bike refuses to start. It sounds quite like the engine is seized: everything fires normally, but come engine turnover all I hear is a grind and a lock-up. And trying to turn the engine by hand is unsuccessful. I have tried pop starting the bike, but when I pop the clutch the rear wheel locks and the bike screeches to a halt.
It looks, feels, and sounds like engine seizure, with the only hope of my bike ever starting again being to free the engine.
But, oddly enough, with a jump the bike fires up and runs normally.

I recently replaced the R/R and tested the charging system, all tests come up clean. Cleaning all connections did nothing. The issue appears even when bypassing the solenoid, and a new battery has also proved nothing. This makes me doubt it's an electrical issue, too.

It seems like maybe the battery I have doesn't provide high enough CCA to start the bike, but that doesn't explain the rear wheel lock-up and seemingly seized engine.

Any ideas?

[sledge]

Could be related to the starter clutch.

Suggest pulling the cover off and taking a look

[esclarsky]

What could be wrong with it? I've checked it previously and everything looked up to par. The issue seems more that the starter motor doesn't have enough juice to crank the engine because the engine is "partially seized"

I took a video of a typical situation

[W201028]

Get a new battery, plates buildup over time, and while it might hold a good charge after hours of trickle or a jump start, it looses amps quickly on its own. That sound youre hearing is the starter clutch trying to pull your flywheel off. Ive had a loose flywheel twice, and I attribute it to trying to milk every battery to its last start.

When the starter turns, it engages the clutch that spins the flywheel, which has a right hand thread bolt. If it spins fast enough to start the motor, then no problem. But when the battery is low, the starter struggles to turn the motor, and when it finally does pass its compression stroke and fires, the engine is turning faster than the starter for a moment. I believe this is enough to loosen the flywheel nut if done many times. Last time I red loctited my flywheel nut down, and I dont run the battery until its on its last leg anymore.