Have you seen these starter clutch parts before?

[coffee_brake]

Here are some photos of the crank, starter and driven gear teeth, and the starter clutch that made me post this video here. This video is a hot start of a stock bandit 1200 that had been getting harder and harder to start while hot for months now. 

Just to recap, it's a new starter, recent valve adjust, new plugs, known good battery by confirming with jumping from a car battery while hot. The problem has been getting gradually worse through all the parts installed and maintenance performed. 

These photos show the parts especially where they may be slipping. I honestly have not seen this before and don't know if I'm looking at damaged parts or not. 

 

 

 

 

 

 

[Upshotknothole]

Crank looks worn, but might just be the photos. Can you feel any grooves on it? I’ve destroyed my share of sprag clutches, they usually blue from heat before they go. Yours doesn’t look bad at all. 

Edited February 27, 2025 by Upshotknothole
Sprag, not spray.

[coffee_brake]

Oh and here's where the sprag holds the large gear

[coffee_brake]

12 minutes ago, Upshotknothole said:

Crank looks worn, but might just be the photos. Can you feel any grooves on it? I’ve destroyed my share of spray clutches, they usually blue from heat before they go. Yours doesn’t look bad at all. 

What ruins these clutches? The video was for you folks, I would never keep my thumb on the starter that long normally.

[Upshotknothole]

10 minutes ago, coffee_brake said:

What ruins these clutches? The video was for you folks, I would never keep my thumb on the starter that long normally.

All the ones I killed were on a trumpet. Weak voltage to the starter will cause problems. Have you checked the connections at the starter relay? 
Troubleshooting starting issues can be a pain in the ass, but you checked with a car battery so that eliminates the battery and the alternator. The end of the crank looks off to me, but if it’s smooth and no actual wear marks, might not be that. 
Just to eliminate electrical, can you check the voltage going to the starter when it’s cold vs when it’s hot? Otherwise it’s gonna be something mechanical. Someone more familiar than me will be along shortly, but definitely double check the crank. 

[Dezza]

What upshot said: trying to start it when there's another problem that results in an inconsistent burst of rotational power from the starter motor can bugger the starter clutch and damage the surface on the crank where the rollers touch, most commonly due to a dodgy battery. The marks on the crank/'orrible noise may therefore be symptoms rather than the underlying cause of the problem. The last times I had starting issues these were due to 1) a build up of carbon dust in the starter motor housing and 2) a dodgy connection due to frame re-coating between the engine block and the frame. 1) was solved by opening the motor and cleaning out the dust, 2) solved by adding an extra earth cable between the starter motor mounting bolt and engine mount. Still check the battery first, then all the other usual suspects such as wiring and the starter relay first as upshot suggests.