starter turning but engine's not

[millard]

The bike's a 2006 F800S, presumably more or less the same engine/starter as the 800GS ?
Anyhow I bought it a few months ago but haven't looked at it much since the initial trial run when all went more or less fine.
tried to start it yesterday after having the battery on charge for a while and the engine turned over fine but wouldn't start. Put it on charge again overnight with an "inteligent" charger thingy which monitors voltage and stuff. Tried again today and the motor is whizzing round fine but not the engine.
took the starter off and put it in the vice to make sure and it spins like a good un when hooked up to a battery.
Any thoughts ?
I'm thinking starter clutch? if so what's involved?
cheers
Millard

 

[Greg Masters]

Take the starter motor off. Hold it vertical with the gear end pointing downwards and spray half a can of WD40 to wash off all the crap that's stopping the pinnion engaging.

Reassemble.

Job done.

Greg

 

[millard]

I thought the pinion was permanantly engaged with the starter gear when in situ?
I was able to put my finger in the hole and the starter gear turns one way freely as you'd expect - presumably the freewheel effect? - and wont turn in the other direction - presumably engine resistance against my finger?

That's as far as I've got with it so if I'm barking up the wrong tree feel free to gimmie a virtual slap round the back of me bonce .
Cheers for the prompt reply.
millard

 

[BroX]

Take the starter motor off. Hold it vertical with the gear end pointing downwards and spray half a can of WD40 to wash off all the crap that's stopping the pinnion engaging.

Reassemble.

Job done.

Greg

What Greg said. Disassembling, cleaning and reassembling did the job for me when I had similar problems.

 

[millard]

Think there may have been a wee misunderstanding here about the type of starter. This one is just a splined shft on the end of the motor which when inserted into the engine casing then engages with the starter gears.
Anyway I removed the offside engine cover and could see the starter gears all being whizzed around by the motor but the engine itself is not turning. The starter ring behind the gennie flywheel turns so I'm assuming it's the starter clutch.
i'm waiting on a call from bahnstormer's techie dept to see which parts I need to order,,, unless anyone knows of an engine being broken for parts ?????

cheers
Millard

 

[Greg Masters]

I've never seen a F800S starter, but I very much doubt that the starter pinion is permanently engaged with the flywheel ring-gear.

On most recent BMWs, the starter motor is a 'pre-engaged' unit. But that does not mean permanently engaged.

When you press the starter button, a solenoid and lever arrangement moves the pinion along the splined shaft engaging with the flywheel as it moves. Shortly after it has engaged, the same movement then connects the starter motor to the power supply and starts the motor turning.

When the engine starts, the starer motor clutch slips so as to prevent the starter motor over-revving.

What seems to be happening on yours is that the pinion is not sliding easily along the motor spline shaft. This is probably because of an accumulation of crud.

So ....

Take the starter motor off. Hold it vertical with the gear end pointing downwards and spray half a can of WD40 to wash off all the crap that's stopping the pinion engaging.

Reassemble.

Have you done that already?

Greg

 

[millard]

I've never seen a F800S starter, but I very much doubt that the starter pinion is permanently engaged with the flywheel ring-gear.

On most recent BMWs, the starter motor is a 'pre-engaged' unit. But that does not mean permanently engaged.

When you press the starter button, a solenoid and lever arrangement moves the pinion along the splined shaft engaging with the flywheel as it moves. Shortly after it has engaged, the same movement then connects the starter motor to the power supply and starts the motor turning.

When the engine starts, the starer motor clutch slips so as to prevent the starter motor over-revving.

What seems to be happening on yours is that the pinion is not sliding easily along the motor spline shaft. This is probably because of an accumulation of crud.

So ....

Take the starter motor off. Hold it vertical with the gear end pointing downwards and spray half a can of WD40 to wash off all the crap that's stopping the pinion engaging.

Reassemble.

Have you done that already?

Greg

Your right Greg it's not permanently engaged with the starter fly-wheel ring gear, but with the starter gears, which in turn engage via a clutch or sprag mechanism to the starter ring at the rear of the gennie rotor.
there's nothing to be gained on this starter by using up a half can of WD40 on it as there is only the splined shaft which rotates, and is engaged with the starter gears when inserted into the cases. On this starter there is no sliding pinion.
I just had a call from the Bahnstormer techie guy who confirmed that it's the starter clutch/or sprag clutch/ or one way bearing (depending on which terminology is prefered) which is at fault and needs replacing.
cheers
millard