The BSA A7-A10 Forum

Technical => A7 & A10 Engine => Topic started by: iansoady on 23.07. 2010 12:29

Title: Oil leak from speedo cable
Post by: iansoady on 23.07. 2010 12:29
There's an oil leak from where the speedo cable exits the gearbox on my recently purchased A10. Before the spanners start flying is there an O ring or something accessible from outside or do I have to take the end cover (and much much more) off to fix it?
Title: Re: Oil leak from speedo cable
Post by: A10Boy on 23.07. 2010 13:05
This in one of those areas that BSA didnt seem worry about. - they all do that Sir. - But they dont need to.

To answer your question you need to know precisely where it leaking from. Is it from around the body of the speedo drive unit, or from inside the centre.

The units are either brass or alloy and push in and are held by a screw into a slot in the body of the unit, then there is a large nut which goes on the thread with a fiber washer behind it, - the washer can leak.

Inside the brass outer is a spindle with a spiral oil throw, there is no seal on this, oil stays in through a combination of prayer and good luck - this also can leak, but when the cable is fitted, if the outer is undamaged and the cable is screwed securely to the unit, the cable should prevent any oil leaks from this center. The problem is that its easy to twist the end of the outer speedo cable when you tighten the nut and this will let it leak.

The best thing to do is just make sure the large nut/fiber washer is secure and in good condition then check if its leaking or appears to leak from the cable.

Good luck
Title: Re: Oil leak from speedo cable
Post by: brackenfel on 23.07. 2010 14:41
I think it may be a case of "they all do that sir!"..

My bike ('61) had a leak ahead of the engine (!), traced to damage in the speedo cable outer where it dips slightly before rising.. I have a new cable to fit but am not confident it will totally cure the problem but then the cable won't ever go dry either.....!!
Title: Re: Oil leak from speedo cable
Post by: iansoady on 23.07. 2010 16:48
I'll have a closer look when I've tackled some of the more urgent jobs.....

The Norton Commando I had for 20 years had a similar leak from the rev counter drive, which was driven in a similar manner by a worm but in that case from the camshaft. There was a mod using an oil seal -perhaps this could be adapted to the A10.
Title: Re: Oil leak from speedo cable
Post by: alanp on 23.07. 2010 17:52
I had a strange leak from the speedo cable itself - basically gearbox oil was winding its way up the cable and peeing out where there was a small cut in the cable outer, up near the speedo.
I was a bit annoyed to think I had to buy another cable for a small cut in the outer and, in desperation, reassembled the cable with the inner cable's nylon sleeve, which is at one end of the inner cable, on the gearbox end instead of conventionally at the clock end. No more leaks (yet, that is). 
If all else fails try that.
Alan
Title: Re: Oil leak from speedo cable
Post by: iansoady on 24.07. 2010 11:07
Thanks for responses.

Coincidentally I popped down to C&D yesterday for a few bits. They were closed, but I bumped into another A10 enthusiast outside and we had a happy hour or so chatting. He suggested that often the gearbox is overfilled causing this, and that the speedo drive gear should normally sit above the oil level.

Something else to have a look at.
Title: Re: Oil leak from speedo cable
Post by: iansoady on 25.07. 2010 12:58
I have just checked the gearbox level and it was indeed overfilled - about 1/8 pint came out.

Looking at the speedo drive bush, according to the parts list I have there should be a nut and fibre washer holding this into the gearbox inner cover, as well as a shouldered screw locating it from the front of the outer cover. Mine doesn't seem to have any provision for a nut / washer as the bush mreley has a shoulder up against the inner cover. Is this perhaps a later version?
Title: Re: Oil leak from speedo cable
Post by: bsa-bill on 25.07. 2010 14:42
Quote
Coincidentally I popped down to C&D yesterday for a few bits. They were closed,
Hope the lads are OK, I read that one of them had been in hospital, I ordered some bushes  Thursday mi-day and still have not got them, that's very unusual for C&D always amazes me how they get stuff out so quick.
Could be they were out getting bits somewhere though, I know they have a day away at times to stock up
Title: Re: Oil leak from speedo cable
Post by: iansoady on 25.07. 2010 15:57
The bloke in the garage next door said that one of the brothers was on holiday so if they're running single-handed at the moment it must be a bit difficult. They were closed yesterday, with an answer phone message saying they'd reopen on 26th.
Title: Re: Oil leak from speedo cable
Post by: bsa-bill on 25.07. 2010 16:39
That explains it then, certainly difficult to complain about the service the pair of them give
Title: Re: Oil leak from speedo cable
Post by: trevinoz on 25.07. 2010 22:43
Ian,
         The late gearboxes have an alloy speedo drive which is just pushed in. No locknut. It should have an "O" ring around it's circumference to seal it. The screw through the cover prevents it from coming free.
Trev.
Title: Re: Oil leak from speedo cable
Post by: iansoady on 26.07. 2010 09:37
Thanks Trev.

I assume the O ring should be between the shoulder on the drive bush and the casing?

Can I remove the locking screw and pull the bush out without removing the outer casing or will something drop into the gearbox innards?
Title: Re: Oil leak from speedo cable
Post by: alanp on 31.12. 2011 15:15
On the subject of oil coming out of the speedo cable itself which mine suffers from, being a bit bored with watching footie on the tele I took a look at the speedo drive and cable bits and confirmed that the drive bits are in really good condition so looked more closely at the cable. The oil was making its merry way past the fit of the end fitting on the cable sleeve and found that the end fitting was loose on the cable sleeving, odd thinks I.
I have refitted the end fitting onto the cable using a Loctite sealant (black, can't remember the number) in an attempt to block the oil path BUT during reassembly I noticed that the inner drive cable/wire was about 5 mm or so too long relative to the outer sleeve and if I forced the end nuts up I would be putting a tension in the cable's end fittings, hence, thinks I, that was probably why one end fitting had come loose on the cable. So, I Dremelled off 5mm or so off one end the inner wire so that there isn't any tension now on the cable.
Unfortunately, being a new year weekend I can't get any oil for the gearbox to conclude this saga but will update you in due course, as they say...

Iansoady, I guess you've sorted the o ring question you raised by now, but if not, the o ring is in a groove in the part which carries the drive spindle and you need to pull off the outer cover to check/replace the o ring or you will only end up doing a nasty to the drive spindle housing by gripping it with pliers and trying to pull it out, god forbid that you do this without removing the locking screw. Taking the cover off is child's play anyhow and you'll get a good appreciation of the condition of the speedo drive bits.
Title: Re: Oil leak from speedo cable
Post by: ian davies on 31.12. 2011 22:30
Hi Ian. I had the same trouble with my A7, i used to stuff the nut with silicon, but it would'nt last for long before the oil started leaking again, a new cable from Draganfly with a different type nut on the gear box end, you can tighten it fully without fear of it splitting, no more leaks.
Title: Re: Oil leak from speedo cable
Post by: alanp on 01.01. 2012 10:46
Later on in the day, after writing my post above about the inner being too long, I sat down to read the Old Bike Mart and lo and behold in the Gagg and Sons advert on page 45 they have issued a warning to readers about cables on the market with the inners too long. I can't recall where mine came from and have a new one on the way from Speedograph anyhow (before I saw Gagg's warning or I would have probably ordered from Gagg). I'll check it out when it arrives. If it's not correct I'll tell them.
Happy new year and may your oil stay in the engine!
Alan
Title: Re: Oil leak from speedo cable
Post by: BSARoadRocket on 12.01. 2012 07:24
I have had lots of problems with leaking speedo and late super rocket style oil pump drive tachometer cables. 
What I discovered was that the oil was leaking out from between the sheath and the aluminum fitting that is crimped over the end of the sheath so no amount of tightening and adding sealant or replacing O-rings will solve the problem.  My cure was simply to carefully cut through the crimp on the aluminum fitting so I could slide it off of the cable sheath.  I then removed all of the old fabric type covering on the outside of the original sheath.  Finally I cut a piece of rubber tubing the length of the sheath and slid the entire sheath in the length of tubing.  I then replaced the crimped fitting which now fits over the old sheath and inside of the rubber tubing and put a hose clamp on each end of the rubber tubing.  Oil leak eliminated.  I have also had new replacement cables where the oil leaks out between the crimped on aluminum fitting and the new plastic coated cable sheath. 

Lastly, the BSA A65 tachometer cable rotates in the opposite direction of an A10 oil pump drive tach.  I believe the A65 cable will fit on the A1O but the sheath and or the cable may be  wound in the opposite direction.  If you put the A65 cable on an A10 the cable and or sheath could essentially use screw action to pull oil out of the motor and fill your tachometer with oil.  I personally have not had this experience but I talked to a fellow A10 rider whose tachometer kept filling with oil and the cable being wound in the wrong direction was the only cause we could think of that made any sense.   A theory to debate I suppose.
Title: Re: Oil leak from speedo cable
Post by: alanp on 12.01. 2012 17:25
I have refitted the end fitting onto the cable using a Loctite sealant (black, can't remember the number) in an attempt to block the oil path

An update on this method - no oil seepage yet.

Reading BSARoadRocket's post it reminded me that after I had sealed the end fittings with the sealant that while the end fittings were off I could have slid on short lengths of heat shrink sleeving and shrunk it over the junction of the fittings with the cable outer. It's a plastic so would have survived contact with any oil.
I'll keep that in mind for the future if I stumble over this problem again.
Title: Re: Oil leak from speedo cable
Post by: alanp on 12.01. 2012 17:33

Lastly, the BSA A65 tachometer cable rotates in the opposite direction of an A10 oil pump drive tach.  I believe the A65 cable will fit on the A1O but the sheath and or the cable may be  wound in the opposite direction.  If you put the A65 cable on an A10 the cable and or sheath could essentially use screw action to pull oil out of the motor and fill your tachometer with oil.  I personally have not had this experience but I talked to a fellow A10 rider whose tachometer kept filling with oil and the cable being wound in the wrong direction was the only cause we could think of that made any sense.   A theory to debate I suppose.

While mine was apart I looked at the hand of the inner wire's spiral relative to the rotation and yes it could conceivably wind oil up the cable which I have had in the past with a cut in the outer. I think that the wire was RH spiral and the drive from the gearbox is anti-clockwise, if my memory is OK.
Has anyone spoken to a supplier to discuss the possibility of getting the hand correct for our babies?