1975 350 MKIII camshaft drive seized.

[themoudie]

Finally, after sitting in my dry workshop for at least 20 years, having previously been stored in a leaking shed and prior to that rescued from a skip, by others, I have started to resurrect the old bird.

Having drained about ½pint of lumpy oil and water from the sump, with a few sparkly particles on the outside of the gauze, this may be a long job and certainly not a fresh fuel, oil change and clean the points job!

The cylinder head was already removed, as were the outer casings, when I got my hands on the bits. Today, I found that the two shafts, within the alloy bevel tower, driving the cam from the crankshaft remained in place and instead of the upper shaft lifting out, it appears to be seized to the lower bevel and it's shaft.

Should there be a collar covering the coupling joint between the two shafts? I suspect that this one has seized solid.

My intention is to use a small nylon headed hammer to drive the alloy tower upwards, out of the lower alloy housing, taking the upper bevel and shaft with it, parting the two shafts. I realise that this may lift the lower bevel away from the bevel on the end of the crankshaft and damage the Z bearing that supports it's shaft. Hopefully, I won't damage the lower bevel and the collar/splined shafts will separate. The whole assembly within the alloy tower has been soaked with Bulldog BDX and will be allowed to soak for 24 hours before using the persuader! Any constructive comments or experiences would be appreciated. Thank you.

Good health, BillR

P.S. the 450 is now approaching 9,000 miles since getting back on the road in 2021 and I hope to use the 350 in a similar manner. BillR

[Bevel bob]

That sounds a fair plan Bill. Its likely that the lower bevel complete with steel bushing and housing will all come out with it . ( Allen bolts removed).but thats all good anyway . The two angular contact bearings are better replaced as they are difficult to assess condition .

[blethermaskite]

Bill, lots of wd40 down the centre oil drain hole in the tower.......leave it for 24hrs then tap the whole shebang downwards if it will go? before trying to tap it upwards.......there is enough end float in the sleeve coupling to allow downward movement and enough movement in the tower itself for the same....so tap down then tap up alternately it should go (unless its very rusty?)
Cheers,
George

[themoudie]

Thank you both for the confirmation of technique. I will just have to take care with the downward hitting, as there is only limited clearance between the bevel gears at the crankshaft end.

Bill

[blethermaskite]

Bill, the bottom bevel clearance is controlled by the bottom twin bearing shimming in the steel housing which which in itself cannot move downwards so GENTLE tapping downwards should have no detrimental effect on the bevels...(unless the control circlips are damaged or missing), better spend a bit of time on this operation .
Cheers,
George

[George]

I had the same problem couple of years ago. At Nigels suggestion I made part to attach to top of bevel tube using the two holes and attaching slide hammer. Still didn't do anything. I ended up cutting opening and distroying bevel tube then using dremel to slit open Oldham coupling sleeve. I think previous owner fitted it with 4lb hammer. Good luck

[themoudie]

Evening All,

Well that came apart!

Another squirt of BDS this morning and then out on the 450 for a canter through Fife and Angus for over 100 miles. Back home and repeated blows to the lower faces of the tower, below the scew holes, using the wee nylon hammer and out popped the shaft and tower. The collar remained stuck to the lower bevel shaft, so more BDS, a little warming with a heat gun and a few taps with a ½lb ball pein saw that come off the shaft.

However, the warm glow of success was short lived! I lifted the barrel off the piston, having already noted that two fins had been lost to the rear of the tower and found that square notches have been taken from the front and rear lower edges of the liner, to accomodate the conrod (I assume?) and the corners have not been radiused, so that the liner has at least one stress crack leading out from the 90° corner!

Then whilst dismantling the clutch ....... New topic!

Good health, Bill

[Duccout]

Hi Bill,

This is the trouble with working on an old engine that has been neglected, there is no way of knowing what damage you will find. Are the barrel fins repairable? If so a new liner will sort you out, and if not, luckily there are lots of used Singles spares on eBay at (sometimes) reasonable prices.

Look on it as therapy, for your brain and body, even if not for your wallet, and bask in the warm glow of ressurrecting another of Bologna's finest.


Cheers,

Colin

[themoudie]

Making steady progress working through the disassembly and cleaning of engine components.

I have attached an image below that I hope is self explanatory, showing the components attached to the upper bevel camshaft drive shaft.

When I pressed the Self Aligning bearing out from it's bushing, the two large diameter shims appearred from between the bearing outer race and the bushing! The inner shim against the bearing is quite dished across its width and I wasn't expecting to find shims between the Self Aligning bearing and it's housing.

I may, MAY, use an alternative 350 cylinder head to the one that originally came in the tea chest, with other parts. So, when re-assembling a new bearing into this bushing should I insert these two shims before inserting the bearing, or should I omit them from the assembly?

And, what do I need to measure to ascertain the correct shimming, if required?

N.B. this is probably a late 350 engine assembled by MotoTrans, or using MotoTrans components, assembled by Ducati!

There is no indication of these shims that I can see in either the Clymer, or Haynes manuals.

Thank you for your time.

Good health, BillR

[IanHood]

I'm a little confused by that picture Bill. Is what you describe as a bearing carrier in the picture pressed into the bevel tube and then the bearing pressed into that carrier? If so, it's very different to what I thought all wide case engines were which is as per the link below:

https://www.ducaticlassics.com/parts/25 ... lve-timing

Ian