37 is your one way clutch, and part 18 is your pinion gear.

So short version, sending power to the stater solenoid, will spin the starter motor and send the pinion gear out to engage the clutch basket as the electromagnet draws the plunger down in the channel.

If the comp (or chain) is loose over on the motor side of the primary, then starter gets a good running start at spinning the clutch basket side, but as the comp is climbing the ramp too much (or too much slack in the primary chain as well), allows for a lot of free run up of the pinon to clutch basket gear, then dam near a dead stop of the clutch basket as the loose comp (or primary chain) cause excess torque between the pinion and clutch basket ring gear (which can shear the teeth/spines off the pinion or ring gear).

The other one, and which can cause the same, is the one way starter clutch is packed with crap, springs are worn out, or engagement points worn, so starter motor is doing full run up itself, but one way clutch is not engaging to spin pinon gear from the start instead (again, starter motor running full blast, but pinon gear not spinning yet on engagement).

Note, one way clutch is to allow the motor to spring the clutch basket, but when the motor starts and pinion still engaged, does not allow the starter motor to be over spun once the motor is started.

So again, engagement of pinion to clutch basket ring gear, since plunger being pulled down is going to send the pinon gear out to engage the ring gear, but since one way clutch is slipping/not engaging from the start/not locking up correct to begin with on the engagement of the two, motor is running full speed, until the one way clutch does catch at some point to lock in that rotation direction, and again, tons of torque when that happens (which can snap off spines of ring or pinion).

So back to starter clutch,

need to pull off end bearing off, which will allow you to pull the one way gear assembly out to clean/check, re lube and re assembly the starter clutch, to make sure it working correctly is it single engagement rotation direction.

And just a quick note, but make sure bolt 6 is still tight/assembly is installed correctly, since pinion front drive parts have to be pulled before you can remove the starter from the primary case back side, and someone may have pulled the starter, but did not install the pinion assembly correctly when starter was reinstalled back in the case.

 

I took one for myself before tossing. Sorry they are not better.



These slivers are the tips of the gear. There were about 5-7 of them. Sorta a clean snap.

 

Looking at those teeth have you pulled the outer primary to look in there ?
If not I'd think it might be a good idea.

WP

 

So it's the pinion on the armature.. I've not seen one go like that but managed to bust a bunch of teeth off one one my FXDX..

You're an ultima guy.. Jireh has them pretty cheap.. Good starter..

I've blown 1/2 dozen starter clutches, 4-5 ring gears, and broke 1 pinion on the starter armature. All of them pretty much from weak batteries on bigger motors..

 

Kind of surprising on a 9ooo mile bike? Time to dig deeper.

 

you have to pull the primary cover to get to the starter jack shaft to remove the starter. Everything looks brand new inside.

 

This was the original 1998 FXDWG Harley starter. The battery is a Agm with 338 CCA and while starting is over 10.5 amps. When dormant it reads 12.8. I did order him a Ultima Starter

 

I sure hope it's over 10.5 amps.. Bet you mean volts.. A 80 ci evo should be no problem..