Starter

Finally got the bloody rotor off after much cursing and fabrication of a puller (my puller claws wouldn't fit behind the rotor), but I first had to chip away loads of Loctite concrete (green) in the groove on the face of the rotor.....

Couldn't get the flywheel off without removing the pick-ups plate, so I hope I marked the washer positions well......Don't fancy having to ponce about retiming the ignition.

Anyway, here is the sprag spring..............Anything look wrong with it?

 

Well........I shortened the spring anyway, first of all by 10mm; then 12mm; then 15mm................None of the alterations to the spring had any effect when the flywheel etc had been reassembled on the shaft and still the strange noise from the starter area and the gears which indicate the starter isn't turning-----but removed the flywheel and starter gear; tried the starter and the gears turn......

......so I finally fitted the spring from a 41mm fork seal, which is really tight..........reassembled again, pressed the starter and behold the engine turned over a few times but not continuously, back to the buzzing sound.......

So, is the starter sprag bearing shagged out altogether?

 

Thanks for that.......it confirms what I read as well........

However, I'm not convinced it will work because the spring is larger than the one that I have used which is really tight and which just slightly improves what is happening with the sprag by the sound of it.......so on that basis, I reckons the bearing needs to be replaced completely.

I did think the battery which has been slowly failing may be causing the problem, but if piddling around with the sprag spring makes a bit of difference, I can't see its the battery......anyway, I think I will change the battery as well and check the starter motor brushes while I have the cover off.

Oh for the days of the Guzzi with its whacking great flywheel and a bendix type starter motor.....sticky bendix fixed in 30 minutes.

 

Well, the starter motor was black dust inside as to be expected, brushes almost new and it works perfectly when bench tested........

 

Got a new sprag bearing today..........

As far as I can see it is identical to the Ducati one apart from a lock ring/circlip in one side (which is probably a later improvement or a different manufacturer’s design) but it shouldn’t make a difference to the fitting.

Unless I post otherwise later today, it looks as though the KTM part 58440026000 can be used on Ducati Supersport carburettored bikes which are fitted with the Ducati part 70140011A (900cc, 750cc, and 600cc) and probably many other Ducatis ie; Monsters and injected Supersports.

Ducati part £118+ KTM part £65

NB! According to Craig at MotoRapido, there is possibly another different Ducati sprag fitted to much earlier SSs, which is now discontinued.......cost a few years ago £200+

 

I only posted it because of the price difference


And now I have confused myself on which way the flywheel rotates when the engine is running!!!

 

Think I have got it now.........cheers.

But which way round should these new type gaskets be fitted or doesn't it matter?

IE Groove side to engine or rib side to engine?

And should 3 Bond be used?

 

Ahh rubbish... When I clicked on this thread I thought it was about food. Bah!

 

It will be.............and I will probably use the same concrete Loctite that I had to chip off, which would have held the rotor on even if the nut had not been fitted.

PS. There is no conical Bellvill washer under the nut on the carbed 750s...........checked with Ducati.

 

Cheeers.......Only if you have the time to scan it, though...........It might tell me how to do it properly!!

 

Loctite 638 deals with that..................once set, you wouldn't even need the nut...........

Broke my puller trying to get the rotor off.....so I had to make one and try that after I had chipped the stuff away from the rotor.....

 

I think what had occurred is due to the 'failing' battery......could be wrong though.......it is still capable of spinning the starter fast when it is off the bike (and I wouldn't like to grab the pinion when it is spinning).

It had been 'failing' for some time so possibly the sprag had not been properly 'engaging' and the spring was well stretched.......the spring also showed signs of damage near the joint, so it needed to be removed before it broke.

The sprag itself may have been alright to re-use if the spring was replaced, but I had decided that I wasn't going to risk doing it all again if the sprag was faulty, bearing in mind I had tried shortening the spring and tried a fork seal spring.

Spent most of yesterday cleaning off loads of old hard Three Bond..........why do people slap it on in huge quantities?

More cleaning to do, then reassembly can start..........I just hope I marked the pick-up plate well enough to get it back in the same position..........I'm still slowly replacing all my 'diagnositic' tools which were stolen in a burglary several years ago; like my timing strobe; carb balancers; gunsons spark plug thingy; arc welder etc.