The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => Gearbox, Clutch, Primary => Topic started by: RogerSB on 24.08. 2017 08:53
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Hi, I'm new here, so here's an introduction.
Earlier in the year I bought my current Golden Flash. I had two GFs in the mid 60s and several other marques, British and Japanese in between. My current A10 was supplied to the dealer in Bristol on 7 January 1960 and registered on 18 January 1960 in Bristol, UK and is unrestored. It has a lovely (not scruffy) patina of 57 years of use. Runs sweet, gearbox ok, starts first or second kick and passed its MOT test in July with no problems.
My only niggle when I first bought it was that it was virtually impossible to select neutral with the engine running (old, old story). With engine stopped it was fine. Then I discovered it had the pre 1960 6-spring clutch. The first thing I did when I took possession was change all the oil, cables, renew a lot of old wiring, removed wheels to check brakes etc., adjusted the chains and had the chronometric (non working) speedo repaired.
The cable I bought was pt no 42-8775 for a 1960 A10 and it was the same as the one I took off, which because the ferrule wouldn't fit in the abutment lug on the gearbox it was held steady against the back of the lug with a washer. Puzzled by this, the easiest thing I could think of doing was to file the ferrule down to size to fit snug in the lug hole (not my ear!). With a bit of adjustment of the operating arm's internal adjuster I can now select neutral with the engine running and the clutch lever is a lot lighter to pull. So happy with that.
Now my cable puzzle. Obviously my gearbox lug is for the earlier cable with the adjuster at the gearbox end. The 42-8775 cable's adjuster is at the lever end only. My first thought was to buy an earlier cable (pt no 67-8681) with adjuster at gearbox end and also fit a slide-on adjuster at the lever. I will mention here that my front brake has the post 60s cable with the adjuster at the lever end and not at the brake back plate end and there is no thread in the back plate lug to fit one - so obviously for the later front brake cable.
My next thought was has the gearbox been changed sometime in the past 57 years for a pre 60s one - highly likely - hence the previous bodge when someone fitted a later cable, probably to fit the original handlebar lever. I know the gearbox internals for pre 60 and post 60 models are the same - so no problem there but can anyone identify my gearbox from the letters and numbers stamped on the case and inner cover?
I'm curious to know if my A10 came out of the Birmingham factory like this, as to be registered on 18th January 1960 it had to be assembled in 1959. So is it a hybrid with the factory using up some earlier parts? Or would it be definitely a post 60s model out of the factory that has had the gearbox changed?
I believe I can get around having to file a ferrule again if I ever need to replace the cable again. I have bought an earlier 67-8681 cable (to suit the gearbox lug) and a couple of slide-on adjusters for the handlebar levers. I've also got a front brake cable (pt no 42-8774) with no adjuster at the back plate end of the cable and room to fit a slid-on at the lever end - so effecting matching brake and clutch lever adjusters and keeping my original levers designed to take adjusters.
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Hiya RogerThat- was epic reading on a phone- at first i thought you were asking about the Speedo cable *eek*; my opinion is the early cable will work nice but use a lock nut on the outside to compensate for not having a thread in the casting, which i will assume to be stock for the era.
Can't comment on the brake- don't have one
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Thanks DuTch for your reply. Sorry for long story to read on a mobile. Done on pc.
There is a thread inside the lug with slot for cable (see pic). It was suggested I drill it out to take the later cable but worried about weakening it and it breaking off - causing an even worse headache.
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Firstly adjust the pressure plate.
Six springer need to be adjusted using a tickler gauge to get them lifting square.
A PIA job , but once done properly it is really a sweet clutch.
Once you have the pressure plate lifting dead square you then back off till the clutch will slip with the bike in gear and front wheel hard into a wall, then tighten them all 1/2 turn.
You will be amazed at just how light and sweet that clutch can be.
Next get a slotted cable adjuster as fitted to most of the unit BSA's.
Slip the adjuster onto the cable then screw into the gearbox.
If you can find one, fit 2 lock nuts, one against the box to prevent the adjuster unscrewing and another at the opposite end to stop the cable popping out of the adjuster.
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*welcome* hope you enjoy the place of good company and vast knowledge ,generously given to anyone who need s help or just a laugh ! Sorry can't agree with Trevor re the six spring unit, *fight* He's a better mechanic than me but if it working leave the thing alone when it stops change it for a 4 springer tri clutch and keep your sanity and ride more often cheers Bob
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I may need to retract my notion that your box is ridgy-didge...maybe/maybe not- not sure when the adjusters were deleted from the box end, but you may be close to the changeover time..... DON'T drill the thread out anyway
My situation is the opposite; has the box adjuster as standard, but have added the '59-'62 lever (happened accidentally but works for me anyway )
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I know we keep going over this but the early 6 spring clutch, (that is on my Plungie) is fine. My gearbox has the threaded clutch cable abutment lug. No adjusters on the handlebar levers.
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Well, thanks for all your replies.
Ridgy-didge??? Had to do a Google search to know what that meant!
As far as I can work out the box with slot and thread in the lug for adjuster at g/box was up to 1959. Changed for 1960 models with straight through hole to take a cable with ferrule and built in adjuster at handlebar lever end. The post 60 cable (42-8775) is what I thought my bike needed but I had to modify it to fit. (ok, . . . yes I know I should have looked at g/box end first).
My clutch is working fine (now I can find neutral). That was sorted by tweeking the push rod adjuster and fitting the new cable. It's just the mix-match that's puzzling me. My GF has it's its original levers for post 60 cables but I've ordered an earlier cable (67-8681) with built-in adjuster at gearbox end and there seems to be plenty of spare inner to fit a slide-on adjuster at handlebar end to fit my levers. Pic attached - see where the adjusting nut is.
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Have to agree about the threaded hole - DON'T DRILL IT OUT! Just fit the appropriate clutch cable. Yes, BSA didn't change everything on the exact date of the new model year. Not unknown for batches of items produced (gearbox castings perhaps?) from earlier years to be used up on later spec models. As is exactly the case with my wife's A10. It has the earlier threaded lug for the clutch cable. We've had that bike since 1972 and are pretty certain that no gearbox changes had occurred prior to that. Nor since. Don't lose sleep over it. It's just what BSA did.
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Hi Black Sheep,
Thanks for your welcomed input. My GF hasn't been restored and is in pretty good condition so I was hoping to hear something like that. As it was delivered to the dealer just after the New Year in 1960 I had the feeling that the factory may have done that sort of thing to use up parts, especially when they were struggling to keep going. Easy to see why and how previous owners may have fitted cables for a 1960 model when it is a 1960 model (like I did), when perhaps they should have fitted earlier ones.
I've had to do some head scratching and searching but I now know I can get earlier cables to fit both clutch and front brake and fit slide-on adjusters with thumb screws at the handlebar levers and then it may be as it was in January 1960.
Photo of my 2nd GF in mid 60s. Rode it Plymouth to Portsmouth most weekends for a year when serving in the RM, took about 6 hours on the roads we had then.
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BUT, if the gearbox was fitted in the factory, there would have to have been special cables made to suit.
Is this likely?
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All I can tell you is how it was with our GF. How it looks now. It was gold coloured when we lashed out £45 for it back in '72.
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BUT, if the gearbox was fitted in the factory, there would have to have been special cables made to suit.
Is this likely?
geez Trev, I can't give a definitive answer, but given some other apparent bodges they did, I wouldn't be surprised; after all, it wouldn't have been that hard to do given that I managed... *smile*
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Well, thanks for all your replies.
Ridgy-didge??? Had to do a Google search to know what that meant!
As far as I can work out the box with slot and thread in the lug for adjuster at g/box was up to 1959. Changed for 1960 models with straight through hole to take a cable with ferrule and built in adjuster at handlebar lever end. The post 60 cable (42-8775) is what I thought my bike needed but I had to modify it to fit. (ok, . . . yes I know I should have looked at g/box end first).
My clutch is working fine (now I can find neutral). That was sorted by tweeking the push rod adjuster and fitting the new cable. It's just the mix-match that's puzzling me. My GF has it's its original levers for post 60 cables but I've ordered an earlier cable (67-8681) with built-in adjuster at gearbox end and there seems to be plenty of spare inner to fit a slide-on adjuster at handlebar end to fit my levers. Pic attached - see where the adjusting nut is.
Maybe the gearbox outer cover has been changed? after 60 years anything is possible.......
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I think it a real possibility that your gearbox has been changed over the years, the reason I say this is because your bike was delivered to the dealer in January 1960. The BSA production runs were from the beginning of August one year till the end of July the next. So 1960 models would be leaving the factory from August 1959, now it is well known that BSA would use up existing stock so some parts during the early months would be from the preceding model. But by January I would expect that they would have been long used up, also at that time BSA was having their best sales so bikes would not be hanging around in the factory.
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Thanks to all. I find all your views and comments really interesting.
The BSA manufacturing years being from August to July could well point in the direction of the gearbox being a replacement and that was my first thought. At the same time for my GF to have been delivered to the dealer from the factory so early in January, taking into consideration the Christmas and New year factory close down holidays in those days (probably a week at least), it definitely would have been assembled in 1959 - but what month or week before the end of the year must remain forever unknown.
Here are pictures of the components, with part numbers in the file names, of what I'm going to use so I end up with matching ends to the cables at the handlebar levers and with the correct end of the clutch cable at the gearbox (whether replacement or not). So there is a cable (with a BSA part no) to do exactly that job.
As for the front brake, the cable abutment lug on the back plate isn't the threaded type - so definitely the post 60 design for the later cable but there is a 42-8774 (1961 - 62) cable that will do the job nicely and being able to use a slide-in adjuster at the handlebar lever to match the clutch.
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Will be interesting if that Clutch cable is made for this purpose and goes straight on with the Adjuster-Style lever (Clamp Assembly 40-8539), without shortening the outer any (as I had to with one I bought by description- part # ?? / overall cable length a bit short )
Be also good to know the cable lengths, mainly difference between inner and outer, which makes it easier to make/modify one for different handlebar.
I cant find a part # for the gearbox cable adjuster, if anyone knows or comes across that could be handy....(?), but do have a part # for the lever adjuster (60-3586 Cable adjuster locknut, 'cam' type, slotted).
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I dont think BSA listed the gearbox end adjuster as a separate part, it was just part of a complete clutch cable. Unfortunately the cables offered now seem to have a hex adjuster rather than the nice, easy to use knurled figer adjusters. I make my own cables and always crop the fittings from old cables and reuse.
Photos show an orignal adjuster and the gearbox clutch cable lug used on bikes with GA7 frames.
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....easy to use knurled figer adjusters. I make my own cables and always crop the fittings from old cables and reuse.
Hmm, that looks great. I wonder if I kept the old clutch cable when I changed mine *doubt* . It is a bit of a pain to get a tiny spanner in there!
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Some info on cable lengths from Romac 1966 catalogue - first photo - and Clarks catalogue from 1969 second.
The Romac does not define what it means by "approx length" but I suspect it is length of inner.
The last 2 photos are also from Romac catalogue. The number and letter code under column marked "Illus. PP4/5" in first photo is decoded in the last 2 photos to show the cable end fittings - for example the 1948/59 clutch cable is illustration 9B.
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Course, as long as the outer can be curved around obstacles what matters in a cable is the amount of travel. If the assembled cable is 20 feet long it should still work as long as the outer vs inner length is correct.
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My cables eventually arrived today, results are:-
Clutch cable 67-8681 fitted fine. Outer is 48” and inner 53.3/4” (that’s measuring them). I've seen them advertised as 48” x 54”. With that extra 1/4” they would be perfect (but that’s repro parts for you).
As you can see g/box adjuster is screwed fully in but the handlebar lever has 1/16" free play after taking up some free play with the lever adjuster. I also took the cover off the g/box and could just feel a gnat’s whisker of clearance between ball bearing and end of push rod. Cable will probably stretch with use and there’ll be plenty of adjustment to go. So I’m happy with that.
Front brake cable 42-8774 not so good. Cable had all the right bits but the inner was a touch too long for my liking. With the brake fully adjusted to give a feeling of confidence the slide-on adjuster’s thumb screw had to be screwed well in along the adjuster and after cable stretch there wouldn’t be much adjustment left – so I reverted to the original 42-8771 cable, which I had fitted new recently anyway.
What I should have done (but didn’t think of it at the time) was measure the 42-8771 cable when it was off (which is a perfect length) and the new 42-8774 cable to compare them because, according to sizes I've seen on adverts, they are both meant to be outer 33” inner 41” – but clearly not all of them are!
Yes, the important bit is inner in relationship to outer.
I suppose these days with all the parts that are affordable being reproductions Julian's method is the only way to ensure you get it dead right.
See photos taken today.
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Hi GB,
I know we keep going over this but the early 6 spring clutch, (that is on my Plungie) is fine.
The plunger and swing arm clutches (six spring) are totally different to each other and cannot be compared *ex*
John
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Julian, those tables are probably useful if the bits are available...
Roger it may be camera angle, but looks like you could probably tweak the pushrod internal-adjuster out a bit(so the arm is parallel to joint at half travel)...?
This thread has my attention, because I have the same setup as Roger on my '52-'56 Plunger built with parts I like or work better, and the lever setup is one of this, but didn't realise it is a actual A10 arrangement I'd been supplied six years ago, until I had to 'replace' the lever due to a truck interlude, (I'd always thought lever setup to be a random aftermarket item).
So- I'll admit that until now I've never researched what part# my Clutch cable should be, mainly as I've generally made up my own from what bits I have, but in 2011, I did buy the new Clutch-cable previously mentioned (where I shortened the outer) by 'description' from this mob in Sydney via eBay; Was/is a nice enough cable, but just a bit short for my liking @ standard length 48" outer/~53" inner and with the nice adjuster in first Pic(red b-ground), second pic is adjuster I've had a long time, and on a 'home-made cable'.
http://trojanclassics.com/ (http://trojanclassics.com/)
Transaction detail from > Trojan Classics< ; CABLE, CLUTCH, BSA, WM20 + most models to 1959. New
Item Number 200541428236$19.90 AUD1$19.90 AUD
(I thought it had a part #, but can't find evidence of it, and there's no M20 parts listing I can find that has the same #)
Interestingly I had a look at Dragans who have useful graphics;
https://www.draganfly.co.uk/index.php/bsa/bsa/a710--b3133--c101112--m202133/category/993-pre-unit-a-group (https://www.draganfly.co.uk/index.php/bsa/bsa/a710--b3133--c101112--m202133/category/993-pre-unit-a-group)
Not much help I guess, and the bottom line is that to have a cable that accommodates both adjusters, may need to be custom (+ ~ 1" inner).
Also had a look on SrM site, but no cables to be found *dunno*