A10 Super Rocket Std Gearbox

[Cyclops]

My S/Rocket has an oil leak from the speedo drive cable exiting the side of the gearbox cover. Removed the nut/sealing washer and squeezed a thin o-ring around the threads. Reassembled and did a short ride. Oil still leaks from the drive but appears to be coming from inside the cable. The Haynes manual shows a spindle with spiral machined on it's length, presumably to throw oil back insde the box. It also shows a washer between the drive shaft and threaded bush. I assume this is either a thrust washer or to help with sealing. Has anyone had this problem and is there a magic cure, short of draining all the oil fron the gearbox(only joking).
The other problem apart from a knotchy gearchange is that it is impossible to put into neutral at standstill. Would be gratefull for any info on how to rectify this. Thanking all you mechanical wizards in advance...

[Richard Mills]

I have had this problem with a 1958 B33. Oil does get into the cable as well as dripping onto the ground, and so will run out of the cable when disconnected. I searched for a drive gear with the 'O' ring groove and ended up buying a NOS one from a dealer in America! It has helped a lot, but has not totally stopped the leak.
I don't think that it is a good idea to seal the joint and cable eg with tape, because of the danger that oil will get pumped up to the speedo and damage it; I don't know if it can pump it this far, but I would rather have it leak out.

[JulianS]

It is common and documented in dealer service bulletins, and for 1960 they introduced an improved bush made from zinc alloy. First photo.

Also the cable ferrule does not seal between it and the cable outer and the oil drips.

The current pattern cables have a hex crimp at this point which does not seal.

The original Smiths cables have a radial crimp which makes a better job of it. Second photo shows a Smiths at the top. Trouble is they are hard to find, last one I got was from a speedometer repairer at an autojumble. You can seal the joint with heat shrink cable sleeving.

I use such on my A10 and it has almost completely stopped the leak and I dont get oil in the speedo.

[Cyclops]

Thanks for the info regarding the gearbox oil leak. The bike is '61 registered so should have the modified bush/drive spindle. Will try using heatshrink to reduce the leakage.
Any idea's regarding the very knotchy gear change at anything other than low revs and failure to engage neutral. The clutch isn't dragging or slipping...

[JulianS]

The gear issue sounds like a classic clutch drag issue.

[Cyclops]

Julian, thanks for the tip using heatshrink. Cut a 4" length just wider dia. than the cable and fitted using hot air blower yesterday. No drips overnight so hopefully might have cured the leak.