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· Registered
30 Posts
Discussion Starter · #1 ·
Hi all,

Sometimes my monster 900 wont start. It feels like the little sprocket is not being moved towards the flywheel.
When this happens, I put it in 2nd gear, push the bike just a little bit, and then it always works again. Untill it doesn't, one day..
Seems like there is something stuck or so.

The bike has a new battery and thicker cables mounted.

Can this be the solenoid? Or is it something that can work again after cleaning it?
Not sure what part of the starter motor causes this failure..

Hope somebody with more knowledge can tell :)

· Registered
560 Posts
It feels like the little sprocket is not being moved towards the flywheel.
It's not a car, the starter gear is in constant mesh with the driven gear.
Sounds like your sprag clutch is dieing.
Sprag ( clutch one way ) is 22 in this diagram but you'll need to get the driven gear 20 off to get at it.

Ready for the bad news?
The parts diagram doesn't show this BUT the flywheel over laps the driven gear.

Automotive tire Motor vehicle Automotive lighting Tread Hood

I haven't had to replace one but I think you'll need the generator outer half and maybe the flywheel off to access it.

· Registered
238 Posts
The Sprag clutch is in the back of the flywheel. Its not a complicated job. You will need a deep Socket for the flywheel nut, A flywheel holding tool and some Gasket sealer for the alternator cover. Its nit more than an afternoons work if you are doing it for the first time and taking your time to do it right. You will also have to drain the oil or lean the bike over to the right.

The Ducati part is expensive (or used to be 3x the cost from BMW or KTM) however .....

Ducati 70140071A
BMW ENA57177
KTM 58440026000

Both the BMW and the KTM parts need to be either installed backwards or have their sprag lobes reversed but work perfectly
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