Sprag clutch locked up

BundyBear · May 30, 2004

The sprag clutch on the '98 600 locked up yesterday. Started it cold on the kick only at about 10 celcius to make sure it would go then stopped it 10 seconds later. It didn't make any unusual noises when it stopped. Tried to kick it 15 minutes later & the starter span with the engine. Removed the intermediate gear from starter & the gear on the counterbalancer seemed springy in the drive direction, solid in the freewheel direction. Rode the bike without the intermediate gear. I'm yet to see if the clutch came good but I doubt it.

How do these clutches usually fail? Several have mentioned slipping but that never happened to this one. Looks like it'll be an engine out.

Starting to think I'm getting too old for this crap.

DezDuster · May 30, 2004

Brad,
You don't want to ride for too long with a locked up sprag clutch even though you've pulled the intermediate starter gear. The freewheel clutch mechanism in the '98 consists of sprags that are in a caged assembly between two races at the right end of the counter balancer. When you engage the electric starter the rotation of the outer race within the starter gear wheel forces the sprags to rotate "backwards' and jamb up the outer race with the inner race effectively locking the clutch assy so that the starter can turn the crankshaft. After the engine starts, and the starter stops spinning, the inner race located in the end of the counter balancer overruns the outer race and frees up the sprags. On the '98 engine the sprag, or freewheel, clutch assy is caged and in the earlier engines the sprags are held in place inside the end of the counterbalancer with a spring wire that runs through them. In either case when the sprag clutch fails the pieces of the freewheel clutch assembly can easily flake off and work their way into the crank case and contaminate the main bearings.
I'm sure that you know you'll have to split the cases to get to the sprag clutch assy. If the inner and outer races are smooth and not worn down you can just install a new freewheel clutch mechanism, but if the races are not smooth you'll have to replace the offending parts. Not cheap.
The alternative is to remove the freewheel clutch assy from the counterbalancer and go with kickstart only.
Most of the time you'll get some pre-warning slippage where the starter just spins without engaging right away, but sometimes it just breaks or wears out, or fails when the engine backfires.
I just went through this with my bike and I took the opportunity to replace all of the engine bearings and seals while I had it apart. Good luck.
Dez

BundyBear · May 30, 2004

Thanks for that Dez. You confirmed my suspicions. I hope the internals aren't too expensive. Without e-start I'll have to get rid of the bike and end the attachment with Husaberg. I just haven't got the strength any more to kick-only it in all situations.

BundyBear · Jun 2, 2004

Pulled the starter countershaft cover off & the sprag seemed to work properly :?: :?: Refitted the countershaft & the starter works fine, clutch does not slip and makes no unusual noises. I know Dez warned me against it but at his point I'm tempted to change the oil, keep an eye on it & see if it it develops.

Anyone had the experience where the sprag temporarily locked up then freed when the engine shook it up as opposed to the usual slippage when cold?

Also, anyone know if using Delo400 instead of full synth 5w50 improves or degrades sprag clutch operation? It is one place where I'd expect to see a difference.

crashnberg · Jun 2, 2004

My '97 501 did that a couple of times when kick starting and i just gave a very short sharp kick at it fixed itself, i have kept a very close eye on the gauze filter though. Not saying its the right way but i'm skint and it hasnt played up since. Jared

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Sprag clutch locked up

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