Motorbike gearbox fitted to a milling machine

8.8 sounds like a metric ? In an old british bike , would have expected BSF,BSW, BSC, or BSP. Noel.

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Hence my comment

MichaelG.

Looking at the links I posted, it looks like the loose bolt is just something that has been jammed in there to blank off the hole where the clutch cable originally went in. So it's a metric thread jammed into a BSW/F hole and has stripped the thread is why it won't come out or go in. So no need to open the gearbox to tighten it.

You will have to try to work it out by levering in the gap with a screwdriver while unscrewing it. Then put it back in place with some epoxy resin to stop the oil coming out if the gearbox is mounted sideways as you said.

PS Unless that loose bolt is now used as the filler plug? In which case, nix the epoxy.

Tap hole to the next thread size up in the list I gave (or metric) and use a dowty washer to seal. For lube go to a landrover spares place and buy 1 or2 sachets of front swivel hub lube. That should work. Noel.

I have removed the bolt at the bottom of the kick start plate and the 7 screws around the edge of the gearbox cover..

Tapping the edge of the cover moves it only about 0.5 to 1mm.

Removing the large cap near the centre (see last photo) , there is a nut holding in a bearing. Is it this bearing that is stuck to the gearbox cover and stopping the cover from moving

Should I remove the nut hoping bearing will be released from the shaft and the gearbox cover will come off?

No idea really. But the linked article I posted says something about taking off the nut and tapping the shaft inwards by an inch or so until it clears the bearing and the end cover can be lifted away. The other end of the shaft will have that pulley mounted on it I suspect, so will need to be free to move when you tap the cover end of the shaft with a brass drift.

Be very careful to keep all shims and spacers and not get them mixed up, so it all goes back together the same way it came apart. You can get the ball bearings out for replacement by heating the alloy housing with a heat gun or propane torch or in the oven at 100 degrees C or so. Best not to drift them in and out cold as it can wreck the casing.

Take pictures before you pull stuff apart so you have a reference for reassembly. Many pictures!

If you google around and find a Velocette forum there should be reams of How To articles with pics on doing these gearboxes, and plenty of Velo experts if you get stuck on reassembly. I only know what I read in those linked articles and previous experience on Norton, BSA , Triumph and Ariel etc gearboxes that are similar but not the same. Velos are a bit of a special breed all of their own. Bit of class though, having a MAC milling machine!

Edited By Hopper on 09/02/2022 11:23:38