On the hi comp early R engines the pin for the intermediate starter gear can elongate the hole on the crankcase, thus making the pin and gears go out of line . Causing binding of the gears. The trick is to use a later alternator cover and an offset pin.
Thanks for that info. I remember reading a bit about that a while ago but you've reminded me of it. I went out earlier to strip down the starter motor and the starter gear to check if it elongated. Thankfully it wasn't! There was no radial play in the gear at all which was good. If it was, I guess getting hold of a later R case cover would be quite difficult and expensive?! I stripped off the starter motor too. Nothing really to report there except a bit of corrosion on the front face and the stud which I cleaned off. Because of the corrosion I'll replace the gasket also. It seems the gasket isn't sealing properly if it's allowed corrosion to form under it. There was no sign of oil leaking through which is good. Regarding operation of the starter, I followed the manual and did the bench test it recommends and the starter span quickly without any issue. There was no visible damage to the starter or to the idler gear. There was no radial play in the starter shaft, but there was a small amount of axial play, im hoping this is nornal?!
The alternator covers aren't that expensive. 1198 or late 848 ones are the covers you need. Those bikes use a steppped pin that sits in the crankcase and the alt cover. Giving support to the gear pin. An offset pin is needed when using the early cases, as the pin bore is in a different position to the 1198 etc. It can be worthwhile doing the mod, especially if the case bore has elongated. Although you would need to make an offset pin.
Getting a bit tired now though. Clutch is on its last legs. Just got a Europa to replace the student 1800 https://www.rk-int.com/machine/europa-vs390/
Nice array of tools though with surface grinder but that is not a Bridgeport mill though, love the retractable leadscrew curtain on the lathe.
After I overhauled my twenty year old starter , there was no radial play and only the tiniest amount of axial play . There were 2 shims on the rear ( commutator ) end of the shaft that I didn't notice at first . I didn't measure them but I'm talking beer can thickness ( not modern beer cans , the thick ones of yesteryear ). Sorry , not very technical , but they must have been put there by Denso . Did you find any ?
Thanks for the info. I'll re-assemble what i have for now but if I start getting problems with elongation or gears binding will deffo look into this further thanks! I wasn't planning on stripping the starter as, having never stripped one before, I was scared of it falling to bits with springs popping out as soon as opened it! However, I've got this far, I'll strip it probably tomorrow evening and let you know what's inside....what's the worst that can hap....actually better not finish that sentence...
I reckon your starter will be fine ..... mine did 80 thousand miles before it started giving any trouble at all . The faults I see with sluggish starters are nearly always caused by tired cables, even if they look perfectly good . Excellent pics BTW .... I've been following your posts .....
Thank you! I like reading and seeing other people's Ducati technical content so thought I'd contribute some of my own to increase the amount of Duc content on the forum! So I spent this evening stripping the starter...taking it apart wasn't too bad....but putting it back together was a bit fiddly!! BUT FIRST...I arrived home to find a present from my 2 daughters in the form of both the arms of my glasses snapped off!! Nooooo! How am I gonna inspect the parts now?! I bought some spare arms and proceeded to fix the glasses first! Damn those little screws are fiddly too!! Eventually got the starter stripped which wasn't difficult. 2 bolts with o-rings on, and then a lot of carefully pulling parts apart... Also, like you mentioned, there were 2 washers at the commutator side, I didn't see them at first either! Then I saw one ..and then another 1 was hidden on the shaft too. Once I started inspecting the parts, I was glad that I did strip the starter too. The commutator copper contacts were all black with carbon deposits. Pretty sure it would work a lot better all cleaned up so I used 1200 wet and dry to sort that out. The next part to check were the brushes. They looked in good shape. Still in place and the thickness of both the brushes was about 11mm. I'm not sure what the initial thickness and the minimum thickness of the brushes should be, anyone? If they are getting to the end of their life I think I'll replace them now. Apart from that I just cleaned up the inside and re greased the bearing with some liquid lith moly type grease. The bearing was in good condition, span freely with no visible damage or notches etc. Eventually managed to get it re-assembled....and I'm not sure if I messed to up or sorted it out....but there is now no more axial play!! My guess is the repacked grease filled the tiny clearance left.
renovating the commutator :- I was chatting to a guy who had worked with DC motors for most of his life . He advised against using wet-and-dry because the abrasive is carborundum which apparently is not ideal for this job . Jeweler's rouge or " rouge cloth " is best , used dry , then a wash down with alcohol ( or switch cleaner ? ) . It looks like wet-and-dry but the abrasive is iron based , rather than silicon and it has a definite reddish colour . I searched online and could only find it in large quantities , so I started pestering local jewelers ( the proper ones , who make and repair jewelry rather than just selling it .... ). I got one sheet each of 800 and 1200 grade ..... not cheap , but I guess it's a lifetime's supply .... Ha ! Probably makes very little difference in the long run , but I thought I'd share the info anyway .
Now you tell me!!!! I knew I was going to wreck something! I get the science behind it, hopefully it should be ok though! Just waiting for the new parts to arrive now so I can put it back together! Also just got a notification that the flywheel holding tool arrived! Also, just wanted to say that I've had a great experience ordering the tool from Michael Shannon. Managed to get the part to me sooner than expected, and has kept me up to date every step of the way!
So, it’s been a while, I’ve been busy with a few other things, and also generally being tired/lazy by the time I do get to work on the bike so haven’t really done much! This ‘project’ was meant to last most of the winter anyway so I’d say I’m still on track ! Talking about track……missing track days already . Anyway! I’m in the dog house so now seems like a good time to spend some more time in the garage! All the parts and tools I need have arrived or been collected, and I also bought a used torque wrench capable of 300Nm which should be close enough with an extra bit of grunt! PS: If anyone does this job in future and needs the tools, feel free to send me a PM if you want to borrow them! Regarding the parts, all of the part numbers related to the sprag had changed since the bike was assembled, and I was intrigued to know what was changed and hopefully improved! So first up, was a parts comparison, new vs old. The flywheel: The differences I noticed were, firstly, the alignment hole for the flange and alternator rotor has disappeared! I’m not too sure why, but maybe clocking the flywheel to the alternator rotor and flange isn’t as important as previously thought, or that the alignment holes were the cause of some unbalance? So they are easier/better balanced without them? There is still a tiny alignment mark to align to the crank shaft though. The second difference is that the holes are no longer chamfered as before. Again, not too sure why. I probably should weigh the parts before I assemble too, just for mental closure. The flange: This is now quite different. I believe the additional holes were originally for weight reduction, however, it seems there were cases of the flange cracking due to the presence of these holes. So the new part is now heavier, but also less prone to cracking hopefully. Again, the alignment holes have also been removed! The clutch: Err….well big differences…one is destroyed, one is not lol. I did play around with the clutch before it was destroyed though, and it seems the spring in the newer clutch is a lot stronger. The old clutch was sloppy and weak and easy to move the bearings, however, the newer clutch is a lot more firm. This difference could just be the usual condition after wear is considered though. The starter gear: I couldn’t notice any difference whatsoever on this part, apart from a pen mark, maybe to indicate alignment?! But it seems way too rough for that, and anyway the starter gear isn’t aligned to anything. Time for a game of spot the difference guys! The flange is now in the freezer, in preparation for assembly! (hopefully the Mrs doesn't find it :/)
One observation on your new flywheel.... the oil feed drilling, next to the alignment mark on the OEM is also missing?
I noted all those changes when I did mine about a year ago. I didn't need to freeze the flange - it tapped in nice and neatly at room temp.
Has anyone tried to resurface the faces where the spragg runs? Or does it put the dimensions out of spec?
