Bevel drive

[lscart]

I have mototrans 250 which I am stripping, taken the head and barrel off and the bevel drive complete with tube is still on the crankcase. For the life of me I can't see how to remove it as the bevel at each end stops it just pulling out!
The Ducati manual is of no help

[ducwiz]

It might be better to look into the parts manual in your case:

Snap 2021-10-24 at 19.29.40.png

1st step: try to rotate the protective tube 0400.29.310. It might be somehow bonded to the O-ring 0400.29.083. If it comes loose, leave it as is for now.
2nd step: the lower and upper bevel shafts are coupled by corresponding flats, facing to each other and held together/in place by sleeve 0400.29.173. The inner surface of this piece ist precisely ground for minimum free play of both coupled shaft ends, which's outer dia's are also precisely ground. The coupling can beseized due to corrosion, ore a previous owner has mounted a sleeve 0400.29.174, which has an undersize bore.
Imho, the only way to get the upper shaft free, togehtehr with the sleeve, is the application of an impact hammer, which pulls the parts off the seizure.
The best photo I could pick from the web:



Of course, you have to make a special adapter by yourself, which grasps under the sleeves flange on both sides, and also connects to the hammer's shaft. A protective shim or ring should be placed between the lower face of the bevel gear and the sleeve's flange in order to protect the protruding circular ridge.

Hans

[elmoi11]

Hello Iscart.
As ducwiz says, the king shaft is only attached to the lower shaft with a tight fitting bushing, but it is usually pretty tight on older engines.

Normally, by levering with two strong screwdrivers, between the bearing and the protective tube, it should come loose, (always little by little, being very careful not to damage the aluminium, and using plenty of oil to soften).

Cheers.
Moises.

[Jordan]

Are you using the Haynes manual?
In it there is a photo that suggests that the normal way to remove the head is to detach it from the bevel tube, which then remains in situ in the crankcase. I have never known anyone to actually do it that way.
If the tube is not unscrewed from the head, it then can be lifted out complete with its bevel shaft, altogether with the head.
But it is odd that yours is so difficult to remove. Maybe there is some tough sealant at the bottom spigot?
I always use a little silicone sealant there because the O-ring can't be trusted in that location.

[lscart]

I have tried the screwdriver method to no avail even played a bit of heat around the area, head scratching time.
Does anyone know where I can get a manual from, I have spent hours of my life never to get back searching the internet/eBay with no results.
Thanks for the input anyway

[lscart]

Just to clarify where I am

[Duccout]

We have been here before! Have a look at the post '175TS with 125S engine' by George, beginning at page 4.

Does the shaft at the top bevel have any play? Is there any play in the aluminium bevel tube? You need to know if the bevel shaft has rusted together at the joint, or whether the aluminium tube has corroded into the lower flange, and I'm guessing from the picture that the aluminium tube is free to rotate, but the bevel shaft is stuck together?

Colin

[George]

As Colin mentioned I had the same problem. The Oldham coupling was seized onto the shafts. In the end I had to cut open the outer aluminium tube and grind a vertical slot in the coupling to split it. I think the problem was caused by previous owner assembled with a big hammer. Should be a sliding fit.

Colin, bought a 1959 AJS 250 today to restore while waiting for DVLA to send Elite registration. Very basic machine certainly no competition against Ducati Singles.

[elmoi11]

Iscart, I have removed many axles in the same situation as yours.
There are times when the joint is very tight. But it is a matter of fixing the motor to the workbench as well as possible (you may have to do it between two people), and use two strong and long levers, between the bearing and the aluminium tube, one lever in each hand, operating both at the same time. So that the shaft rises upwards.

Slowly, patiently and with plenty of degreasing oil.

Cheers.

[Duccout]

Hi George,

Good luck with the AJS, pleased to see that you are still bitten with the restoration bug. It never ceases to amaze me how many old bikes survive, you would think that once a bike was a few years old it would have ended up on the skip, but possibly it is down to owner's love of their 'old bike' that ensured that they survived. There are so many Ducati Singles being restored now that I reckon that there are more roadworthy examples now than there were in say, 1980.

Colin