Author Topic: gearbox oil level  (Read 11187 times)

Offline KJ WestOz

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Re: gearbox oil level
« Reply #15 on: 24.01. 2021 02:54 »
Does anyone know how to stop the speedo drive leaking, theres no seal and its actually below the level of the oil.

Hey mate. Correct;  is no seal mentioned in any of the diagrams as far as sealing the cable.

The shaft is held into the housing and there is a seal there that stops oil coming out of the OUTSIDE of the speedo shaft drive gear sleeve. That is shown in the parts lists. I have found that IMPOSSIBLE to get. It is a square section seal; EVERYONE sells "O rings" for that; it is NOT meant to be an o ring; it is meant to be square section. I finally found one guy who had the correct one. When it arrived; it was ancient/hard/cracked = useless. So I put my old one back in.

But as far as any way to stop oil running along the shaft and into the cable? There isn't any shown in the parts list. You are correct in surmising that the oil level is ABOVE the speedo drive shaft level, so it runs down it and lubes it.

On mine, it had either an O ring or fibre washer between the cable jacket end flange and the shaft holder/outer end face.

I honestly can't remember whether I used an O ring; but I think I did.

So my estimate of how it works is that oil runs down into the cable jacket and sits in there. I have NEVER seen a drive cable meant to "hold oil" in the jacket. But every time I have removed my speedo cable - that bottom few inches = full of oil.

My bike sat for almost 40 years with NO oil leaks at all.

I have just rebuilt it and replaced everything; and am working my way back putting some old parts back on; because new ones leaked; old ones didn't. :P

But the above method of "letting oil into a cable?" Weird; but the only way I can see it can work. There is a scroll feed on the shaft that will pull oil back into the box; but when sitting just allows a spiral path to allow it to run out.

Mine is back together now and not leaking so far. (Fingers crossed). It didn't leak before (sat for 13 years over same paving; not a drop - (not many Brit bikes can say that; Trident next to it is a sieve!!!!); but I am lucky enough to have used old speedo cable; and after my disastrous experience with "new" cables; one that I know works/doesn't leak is a godsend.

I hope the above drivel makes sense.

But it is a quite flawed idea - or seems so. Works on mine tho.

Offline Slymo

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Re: gearbox oil level
« Reply #16 on: 30.01. 2021 02:39 »
I put straight 50 in my A10. This time I've also added some Moreys for oil. Seems to be fine. I did try 20/50 once out of necessity but it did make the third gear howl more noticeable.   I've also heard the viscosity ratings for engine and gear oils are not the same and that 50 grade engine oil corresponds with around 70 grade gear box oil. Anyway with straight cut gears there is no reason for EP oils and I hate the stink.