Starter motor issues

[Loomesy]

I have issues with the starter motor on my '88 Dommie.

When I press the starter button, the starter motor spins but doesnt engage, and will only occasionally catch and start the bike. I have checked the motor assembly under the cover where the starter motor enters the engine and that is fine, so either the problem is within the motor itself or within the engine...wondered if anyone had any experiences of this (there is a kickstart but thats tiresome especially when stalling in traffic as dommies have a habit of doing...wicked sense of humour dommies have).

Also theres a whine coming from the engine similar to the geared camshaft whine of a vfr400....is this normal (it has done only 17000 miles(apparently)), my other dommie didnt do that but it had more miles on it...

Cheers, look forward to the responses

[SquarePants]

If the starter is spinning but the engine isn't turning over then it sounds like it might be the starter clutch (sometimes known as the sprague clutch). It's a one way clutch mechanism that sits on the lhs of the crank and turns the crank over when you press the starter switch. Once the engine is running and you let go of the switch it releases it hold of the crank and then stops stops spinning along with the starter motor.

Think of it like the ratchet mechanism in your socket set. When you're doing up a bolt it only grips when you turn it clock-wise. If the ratchet mechanism is worn or broken it slips when you apply any force to it. I'm guessing this is what happening inside the Dommie.

Sorry it's a crap explanation - here's a link to some chat and photographs about the sprague clutch for a BMW F650 - it looks fairly similar to the Honda's set up.

F650 Sprag Clutch FAQ

[KirriePete]

If it goes "Whizzz! Whizzz! (Repeat for ages) Whizzz, crunch, cough, start" it's the clutch alright - most likely the inner, a ring of little cam-shaped doobries, like ... errr click here for a picture (and price).

You'll need:

Rotor puller - £20 or so from Silvers
L/H Engine cover gasket
New inner clutch - see link above

Drain oil (or lean bike over to the right)
Remove engine cover (watch for the clutch cable & neutral light cable)
Undo flywheel nut - you'll need to lock the rotor somehow - I used a strap wrench and jammed some towelling in the gaps
Use puller to pop rotor off and there is the starter clutch mechanism in all it's glory. The big ring should only spin freely one way, if it moves more than a millimetre (really!) the wrong way, the clutch is buggered.

Pretty obvious how it all goes together once you're in there, reassembly is the reverse of ..... etc.

Time taken, including draining/refilling the oil and faffing about locking the flywheel, just about an hour.

You're welcome

[Loomesy]

Ahh ok excellent, thanks for that, I'll sort that out in due course (once accumulated some monies)

Any ideas about the engine whine?

Thanks again

[SquarePants]

Sorry, no idea about the engine whine. Mechanical whines are usually down to gears or bearings of which there are quite a few. Is it possible to tell more precisely where it's coming from? Does it only do it in a certain gear or all the time?

[explore]

Originally Posted by Loomesy

I have issues with the starter motor on my '88 Dommie.

When I press the starter button, the starter motor spins but doesnt engage, and will only occasionally catch and start the bike. I have checked the motor assembly under the cover where the starter motor enters the engine and that is fine, so either the problem is within the motor itself or within the engine...wondered if anyone had any experiences of this (there is a kickstart but thats tiresome especially when stalling in traffic as dommies have a habit of doing...wicked sense of humour dommies have).


Cheers, look forward to the responses

im having exactly the same problem at the moment starting the bike, 95 model , the starter clutch sometimes spins the wrong way, its also know as a one way bearing, which im in the proses of changing , its a relatively easy job, but it requires some specialized tools to remove the fly wheel, which i don't have , I've started another thread ill let you know how i get on ; flywheel removal