So whats the final outcome then Simon ?, Is the BMW part worthwhile or would the Ducati/Aprilia parts be a better bet ?.
I did find 2 distinct part numbers for the BMW sprag
ENA43296 & ENA57177, one has a heavy flange on the bottom and the other does not, also the "balls" as I call them look differant.
I'm writing this up with some other tips but here is what I have so far:
OK. Just spoke to Royton at REPS (
http://www.repsmotorcycles.co.uk/) and he gave me the low-down on 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:
http://www.motorworks.co.uk/bmw/products/product.php?f=b&bke=bmw&q=ENA57177&x=27&y=9
I’m assuming that is a BMW part number (anyone confirm?) as opposed to a Motorworks one but anyway, it’s just a sprag clutch for a BMW F650 (circa 98, 99, Royston said, if you want to be specific).
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
www.speedaway.co.uk and they had both housing and gasket to me next day.
So yes, it's a go with the BMW sprag!