Oil leak through speedo drive

[roadrocket]

Hello!
I have experienced that my gear oil level is in danger of dropping very quickly through the speedo drive. It's not easy getting at the nut that sqeezes on the copper/rubber seal there. Is it just one of those things, or should I get a box spanner and give some tightening?

Otto in Denmark

[fido]

Yes, they all do that, sir. I suppose all the gearbox oil leaks could be cured but only by modifications like O rings etc. If you think it's getting down the nut threads you could try a bit of PTFE tape.

[groily]

Which worked brilliantly on mine Fido - 400+ kilometres this weekend, from slow country lanes to dual carriageways, and NOT a drop of oil from anywhere, top, bottom, primary case, speedo drive . . . Huge outbreak of pride - but sure to be temporary!
Except for one remaining thing . . . the small weep from the kickstart shaft.
However, the answer to the original Q has to be, if the oil level is dropping noticeably and fast, Yes, get the tool and do the thing up so at least it's just the semi-normal dribble rather than a flood! And best check at same time the oil isn't actually leaking from somewhere else and then trickling across and along and whatever, to make you think it's coming from the speedo drive box. At the final drive end, the small allen screw that locates the selector rod can be a source of leaks, and so can the mainshaft/sleeve-gear itself, as well as the obvious gasketed joints, the felt seal on the inner chaincase (esp if the chaincase is overfilled), the cam-plate plunger assembly on the bottom, etc etc. It often looks as if it's 'just the primary chaincase, as usual', when it's actually a bit more complicated . . . Hopefully not in this case though.

[LJ.]

An old thread but always worth adding to.

I'm investigating an oil leak from the speedo cable... But leaking from the top of cable where the it attaches to the speedo itself. I'm thinking here that it might be because the inner cable is the wrong way round. Am I correct that the brass ring with it's fibre washer, should be gearbox end??

Of course as per recommended from fido and Groily, I'll be fitting an 'O' ring and some PTFE tape!

[Rusty nuts]

LJ

It should be speedo end, the idea being to stop grease working it's way up the last few inches into the speedo.
The cable should be lightly greased not oiled, as some suggest.
Oil frome tired gearboxes will work its way, in if it's a problem you could add an o ring.

Cheers

Rusty

[cus]

G'day All,
My cable conn. leaked a bit also, I used rescue tape (Magic Stuff),
it's a silicon type tape, that when you wrap it around & stick it back
on itself, forms a complete "O" ring type seal, it kind of melts together,
a bit hard to explain, but its very handy gear. I also use it for all
my elactrical ties, doesn't harm the frame paintwork.
You wrap it around the frame tube over the top of the wiring,
then roll it up the tube & it forms a neat "o" ring.
 Look it up on
the web, comes in all coloures, I mainly use black & clear, can also
withstand very high temp. I've done over 2000 miles & had no oil
come out of the cabble/gearbox connection.

regards, Cus

[bsa-bill]

Don't know for sure Cus but is this the stuff they call "self amalgamating tape)?.
I always intended to get some ( bound to be useful ) but never have seen it in shops, or when I've had it in mind when browsing.

[muskrat]

That's the stuff. A mate of mine (aircraft mech) put me on to it. Costly but good.
Cheers

[bsa-bill]

Found some on Ebay, with the project to wire up it could prove usefull

[A10Boy]

I seem to recall that there should be an O ring or washer at the end of the speedo cable.  Also, when you tighten the nut, hold the metal fitting on the outer cable with grips as this can turn on the outer, break the seal and any oil that leaks into the cable will leak out all over the bedroom floor.

[KeithJ]

Some time ago I purchased a O ring for the speedo drive from one of the more reputable suppliers but can't recall which one.  I thought it was a standard part but can't see it in the parts list book I have.  Is the O ring listed as a standard part or is it a modification? 
ATB
Keith

[trevinoz]

"O" ring is fitted to the late alloy type speedo drive. Early brass drive just has a fibre washer under the nut, which the late drive doesn't have.

Trev.