Sprag, which one and where do I get one?

Hi all

Just started using this forum so i'll introduce myself, friends call me Raz so thats good enough for me.
Bought an Aprilia RSV Mille last year been out a fair bit on it since then but of late it's been tucked up for the winter months, I would have got it out of wraps for a spin before now but I have a problem, I suspect the Sprag Clutch is buggered as it sounds like a bag of bolts when I hit the starter button.

So my first question for all you Aprilia hard core dudes is where can i get a replacemeant one that doesn't cost the earth? I've read a few posts on Sprags, some of you suggest a Ducatti equivalent or BMW sprag does the job and are cheaper than Aprilia parts. What I realy want to know is what one definately fits, do they need modified or not and where can I lay my hands on one?

does the engine run fine? did u take it round the block? or did it not start at all?

I have the ducatis in my bike, it works plug and play , you can get it at a ducati dealer just tell him the serial number(probably somewhere on this forum).

The BMWs part just needs to be rotated.

clanking noise appeared bike started once or twice after that and runs fine but clanking noise there all the time now and doesn't want to start and I don't want to keep trying it for fear of causing any more damage

Rotated???

If you can hear your starter motor spinning but the engine is not turning over, the sprag clutch assembly has failed.

I've pretty much concluded the sprag clutch is shagged, where can I get an equivalent replacement (Ducatti, BMW)? Part numbers? I'm in Scotland so nearest would also be good?

0659110 is aprilia part number for a clutch sprag
0634595 is aprilia part number for a clutch sprag gear
with one do u need

Here you go mate, here's my notes on using the BMW Sprag


If you assemble the sprag the way the Aprilia one comes out (with the flange trapped between the flywheel and outer housing) it will lock the wrong way (which I might have seen if I’d taken notice of the direction arrow on it!).
The BM part (and, Royston reckons, the Ducati part as well) has a smaller, tabbed flange which looks like it should fit in the milled recess on the back of the sprag housing.
Royston reckons he fits them the other way, with the tabbed flange between the large drive gear and the housing. He says he’s done several this way and at least one local bike he knows of is still starting strong three years later (the others he hasn't had back so ...).
To my relief, he also says that when he first used the BM part, he rebuilt the sprag to run the other way – just as I did – and it was fine.
The other query I had was the spring clip. The Aprilia part has small slots for the castellations on the clip to fit into: The BM part (and, according to Royston, the Ducati part also) just has gaps in the bearing cage, so gives no postive lateral location (you’ll understand what I’m on about if you see one). Royston says ‘it’s not going anywhere so don’t worry’ and he’s done enough of them to know.

So here’s the part:

BMW Sprag


You may find it even cheaper than this but I’ve dealt with Motorworks before (er, 1989 actually) and they’re top blokes – had this in stock and got it to me next day (think it was about 65 quid with postage).

For the housing and gasket, I tried the ususal suspects who were very nice but quoted around 5-7 days from Aprilia – and we all know about Aprilia parts delivery times. So I phoned Speedaway Motorcycles and they had both housing and gasket to me next day.


So yes, it's a go with the BMW sprag!

PS. Strip it down first and inspect the sprag housing because you might get away with just the clutch bearing itself. I've even heard of people cutting and retightening the spring - which is the part that usually goes.
If you need to borrow the flywheel puller and crankshaft holding tool, let me know and I'll post them to you.

Also, have a read through this thread and see this

Trick to getting the flywheel off is plenty of heat (about 10 mins with a blowtorch) on the centre boss. If you need any more help, feel free to ask.

What part number is this make for BMW or Ducatti?

I need one that fits my Aprilia RSV Mille 2000model

If I can get a cheaper one than the Aprilia part that definately fits then all the better!

Suppliers names, addresses etc would be helpfull

Thanks A303

Do you know the part number for the BMW Sprag?

Raz, I've just edited my last post and put a link in there, have another look and should all be clear now.

Cheers for that dude, very helpfull!

I'll let my mechanic deal with removing and replacing it, sounds a bit to technical for me to attempt, and if it doesn't work i can blame him

Don't forget to make him Loctite that flywheel on or wave goodbye to your crank.