The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => Gearbox, Clutch, Primary => Topic started by: frankenstein on 15.10. 2008 22:38
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hi....just an easy question for anybody...how do i know when the gearbox oil is at the right level....how do i change it....and what oil is best !
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Frankenstein,
There is a drain plug in the bottom of the gearbox to drain the oil. Drain it when its warm or leave the drain plug out overnight to get out as much of the old oil as possible.
Just behind the kickstart there is a level plug, take this out and take the oval shaped cover off the side. Tip oil in until it just starts to come out the level plug. As to the type of oil, you will probably get a dozen different suggestions but I have always run a standard 80/90 gear oil with no problems.
I would suggest you get yourself a workshop manual of some sort, even a basic one will have this sort of info in it.
Brian.
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Frankenstein,
I would suggest you get yourself a workshop manual of some sort, even a basic one will have this sort of info in it.
Brian.
I just looked through the BSA service sheets book and there is no mention of renewing or topping up the gearbox oil *conf*
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thanks brian for the info ... i have just orderd a haynes manual at last..my mate has one..but to be honest i find this forum miles better for information... *smile*...i will take a look at getting that 80/90 gear oil next week !
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fido is correct; the OEM Service Sheets make no mention of any oil change except for the engine. I believe BSA was quite remiss in this matter.
For 'BSA Servicing', J.B. Nicholson's 'Modern Motorcycle Mechanics' suggests a gearbox drain and refill at 5000-mile intervals, or "seasonally if there is substantial change in temperature." Engine oil is
recommended.
Face it - gearboxes leak, ingest water and produce metallic debris. Oil is cheap.
Nicholson suggest the same interval for the forks and primary, too. His 700+ page book is encyclopedic and was very much read during and after its four-volume run.
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Frankenstein, the Haynes manual is as good a place as any to start. By reading the sections and looking at the illustrations you will be able to work out most things.
The manuals do say to use engine oil but I have always used gear oil. Gear oil is made for use with gears plus being heavier (thicker) is doesnt escape quite so easily.
Good luck with it all. Brian.
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Brian and others,
Does the use of gear oil result in any difference in the feel of shifting or, perhaps, locating neutral?
Richard
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Richard, I havent been able to detect any difference between the two oils. I have been using gear oil for about twenty years now and run it in all my bikes including the gearbox of my modern Moto Guzzi.
I probably should add however being in Australia we dont have the extreme cold that some would have, winter in the UK for instance. So for anyone living in the colder places maybe the engine oil would be better.
I found the gear oil didnt seep out around the kickstart and gear shafts quite as easily.
Brian.
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Good question Richard. I've been using 80/90 in the A for a while and it's less leaky for sure, but I do think neutral can perhaps be harder to find sometimes (cold mornings). I put the thicker stuff in when I had to change the sleeve gear pinion last year, in the faint hope that it might be helpful when running non-matched gears at that end. I'm not claiming the A's clutch is perfect or perfectly adjusted always, but my B31 is running on engine oil, and it IS easier. (But it's also a less worn, lower-stressed 'box and has a longer shift lever . . .). People used often to say that some HP/EP gear oils' additives could eat bronze bushes. Not sure about that not being a chemist, and nothing's been eaten hereabouts that I can detect.
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I'm currantly using EP140 in all bikes, boy it is thick! and with some recent cold days it has been noticable too. Between the two A10s I have I could tell which is a tighter box and which is looser. The gear changes on the tighter box have been interesting, easy, smooth, non clunck changes and neutral has been easy to find too. Certainly has been leak free this summer.
Has anyone tried waving one of those telescopic magnets about in the gearbox? you'd be suprised at the amount of swaff you fish out.
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Does anyone know how to stop the speedo drive leaking, theres no seal and its actually below the level of the oil.
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I have always used straight 90's.. I bought the bike in 1979 and am still unfamiliar with the internals of the gearbox to this day! I have re-built the engine four or five times in that period (33 years) but the box is still perfect..........A decent enough road test I would suggest?
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G'day metalflake11, dug up an old one there.
I agree, the BSA box's are great. I raced the cafe for 7 years and now on the road for a few with only yearly oil changes. The '51 had a bent selector due to my heavy right boot, only prob in 30 years. The '64 broke a dog off 3rd/4th. I use 80/90 and add Nulon.
Cheers
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Hello Muskrat, Yup, good solid bit of engineering!
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And back to the original question.
Any oil will do.
BSA specified engine oil because gear oils in those days had a lot of sulphur in them which ate out bronze bushes.
Now days most gear box oils contain either less sulphur or passivators to prevent this reaction as most car boxes are synchromesh and syncro cones are generally brass.
So if in doubt ask if the oil is "syncro safe " if the answer is yes then you are in business .
Even better is most modern gear oils also contain addatives to prevent oil seals hardening, a bonus.
Having said that plain old engine oil will do nicely and won't do any damage.
The lighter the oil the less drag in the box the "sharper" the change and the more horsies at the rear wheel.
I have just gone to "liquid grease" in the WM 20 box ( till I do the over due rebuild ) and that has knocked a good 10 mph off the top speed and made the changes really slow
Good that this thread has come back up
The person who told me to use 00 liquid grease obviously never rode very far.
IT is too thick and totally destroyed that box
The layshaft bush never got anywhere near enough lube & wore oval.
This put pressure on the selector forks causing them to wear away to next to nothing
All of bushes inside the gears were destroyed as well.
The total box was trash, only the cases & mainshaft were salvagable .
Lesson learned the very hard way, put up with the leaks and use the correct grade of oil in BSA boxes .
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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.
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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.