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Another Pantah Rebuild

Discussion in 'Builds & Projects' started by Derek, Mar 22, 2016.

  1. I notice that the Pantah workshop manual which was written in 1979 shows a solid pinion with no holes. Presumably the holes started from 1980 onwards, so almost all Pantahs will have them.
     
  2. Indeed, and all later models have the oil pressure switch elsewhere.
     
  3. Good point. How could I have confused one screw head with another?
     
  4. Indeed. There must have been a major redesign between Pantah and the 906/907 which are basically the same bottom end as the 851/888/916/900SS. I'm less sure about the 600 and 750 variants.
     
  5. The starter is now back together and back on the bike. Apart form looking a bit grotty outside it was fine internally. Looking at pictures and diagram I can see that on later bikes the starter mounting holes have been rotated slightly anti-clockwise to bring the rear most screw directly behind the intermediate pinion. They must have worked out that it wasn't really such a good idea to have to take off the flywheel to change the starter.
    I've now had the clutch side cover off to check on the plates, they were well stuck together but otherwise good, and also to fit a new crankshaft oil seal, since the pressure to the big ends depends on it.
    A question. Which way round is the gearbox sprocket meant to go?
    The manual doesn't say and none of the pictures are clear enough to make out. If the boss is inward the sprocket doesn't go on far enough to clear the slot for the retaining plate. The flat side of the sprocket has the splines recessed so that it goes fully onto the shaft, so I'm pretty sure it should fit with the flat side inward. Or I have the wrong sprocket [​IMG]
     
  6. The flat side of the sprocket goes inside towards the gearbox (as shown in the spare parts catalog), and the oval flange is on the outside where the locking plate goes.
     
  7. Thanks Pete, that confirms what I thought.
     
  8. If anyone is interested I've created a colour wiring diagram for the 500SL. The colours make it much easier to follow wires.
     

    Attached Files:

    • Like Like x 1
  9. Excellent, this is most helpful. Many thanks.
     
  10. An update on where I've got to. As I said above I've had the frame, swinging arm, etc re-powder coated. I've decided not to strip the engine but have had the heads off. The bores are in good condition, not surprisingly as it's only done 18,500 km. There is evidence that both inlet valves have touched the pistons, very lightly by the look of them, and both inlet valves have been replaced. Sounds like somebody messed up the timing when fitting new belts. I'm still waiting on one shim from Lacey Ducati before I can get the horizontal head finished and the engine buttoned up.
    In the meantime I've stripped the brakes and rebuilt them with new pistons and seals. I have just stripped the carbs, cleaned them and rebuilt with new gaskets, o-rings and float needle assemblies from Ducati Paddy. Paddy is great to deal with and provides a very quick, personal service. I'd recommend him if you need bits for a bevel or one of the early belt Ducatis and he stocks Dell Orto and Brembo spare at good prices.
    Incidentally, interdental toothbrushes are great for cleaning out jets and passageways in the carbs. I used the smallest 0.45mm ones.
    I've also repainted the dash panel and cleaned up the clocks which came up a treat.
    The plan is to have a rolling chassis as soon as the engine is back together. Next step will probably be to get decals, arrange for the paintwork to be done and have a few bits re-chromed. While that's happening I'll get stuck into the electrics and fitting the other cycle parts.
    Hopefully have a picture to post soon.
     
  11. I'm still waiting on a 1.6mm opener shim so that I can get the horizontal head back on. In the meantime I've got fed up waiting and decided to start building the frame around the engine and I'll fit the horiz head after the shim arrives, hopefully this week.
    I got the frame bolted on and the front end together. I fitted the swinging arm but found that one (or more) of the shims to take up the sideways movement is missing. With the shims fitted I have a 2.3mm endfloat with it assembled. There are 2 shims fitted, one is 2.5mm and the other is either 0.5mm or 0.8mm ( I haven't measured it yet). Raking through my bits and pieces I found a suitable shim at 1.8mm and have made another at 2.0mm. With what I have it's likely that I'll end up with 0.3mm (0.012") endfloat. I feel that this is too much. Any thoughts?
    Also, where the hell does the chain guide fit? I have the chain guide with 2 screws to fit it, but what do they screw into? There is no where for it to go on the underside of the swinging arm and I can only see 1 spare screw hole in the crankcase behind and below the sprocket.
     
  12. The chain guide does not attach to the swinging arm, nor to the crankcase. The two M6 x 25mm screws go into the frame bottom bracket, just above the left pivot point of the centre stand. The screws go in with the heads to the right and the threaded ends to the left.
     
  13. I think 0.3 mm is too much. The workshop manual is vague and unhelpful on this point, but may I suggest 0.1 mm?
     
  14. Thanks Pete. I thought you'd have the answer. :upyeah:
    This is just one of the many problems that turn up when rebuilding a bike that was stripped down by somebody else.
    Thanks Pete. I thought you'd have the answer. :upyeah:
    This is just one of the many problems that turn up when rebuilding a bike that was stripped down by somebody else.
     
  15. That's my thought's too. The manual is vague and unhelpful about a lot of things.
     
  16. Well I got the swinging arm shimmed down to 0.1mm by making a few assorted shims.

    I then stripped and rebuilt the electrics panel that mounts behind the steering head. Jeez! What a mess - 34 years of accumulated oil and road muck. I spent an afternoon degreasing and cleaning all the components. I realised when I came to put it back together that I should have taken a few photographs first as I had to work out where all the bits went and everything had to be put back in a particular order because some of the screws are obscured by other components but I got there.

    The question I have now is about the charge warning device. The one shown in the diagram is a Motoplat Voltimeter, whereas the one fitted to my bike is made by Ducati Elettrotecnica and of course they're not the same.
    The Motoplat has 3 terminals; earth, switched ignition and one to the warning lamp.
    The Ducati one also has 3 terminals but it earths through the casing!
    The terminals are marked; B+ ( battery?), A (no idea), L (to warning light?)
    The parts list shows a red wire and a blue wire for connecting to the charge warning device but of course no indication of what they connect to. I have the red wire.
    Anyone know which terminal connects to what?
     
  17. The charge warning devices are totally useless and always go wrong, usually creating other problems as they do so. I suggest omitting it altogether. The bike will work just fine without it. If you are really keen to fit it - well, good luck with that.
     
  18. Ha Ha! Why am I not surprised? I thought I'd give it a go anyway. If it doesn't work I can use one of these which I highly recommend. I have one on my 907ie. After I fitted a MOSFET regulator I didn't like having a redundant light in the dash :rolleyes:
     
  19. I haven't posted about this for a while. In the meantime I've been spending loads of money but still just had a pile of bits to show for it. In the last couple of weeks though I've been making some progress. The engine is fully assembled, the frame has been bolted to it and with swinging arm, forks and wheels added I now have a rolling chassis.

    [​IMG] Click this bar to view the original image of 1200x673px.
    [​IMG]

    I had a a helluva job bleeding the front brakes but have now got some pressure although there is still some air lurking. The wheels have yet to be painted but I'm leaving them with the 20 year old tyres on until the bike is a bit nearer finished. I don't see any point in fitting new rubber just for wheeling it about the workshop.
    I now have the correct graphics and will organise the paintwork in the next week or so. In the meantime I'll get started refitting the wiring with an updated fusebox and new connectors where necessary. Some bits have been sent off for re-chroming.
    The aim is to have it running by the autumn and ready for the road for the spring.
     
    • Like Like x 2
  20. Excellent. Paddy usually has suitable fuseboxes in stock:
    Electrics
    ... but you probably knew that.
     
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