Author Topic: BSA braking  (Read 1648 times)

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Offline AdminPete

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BSA braking
« on: December 07, 2008, 12:31:13 pm »
From: ozkoz6  (Original Message) Sent: 20/09/2008 00:36
I know BSAs have a deserved reputation for having inadequate brakes. Mine's a 52 year old C12.

I know when I ride to allow for this and leave lots of room ahead and be more critical in observation.

I had an emergency stop the other day and when I applied the brakes it was like they didn't exist, especially the rear one. Nothing happened, I swerved to the side and missed but I sure didn't enjoy the rest of the ride.

I've been thinking since of changing the front wheel to some more modern thing that includes a disc brake. I know it's not keeping the bike original but I think it's better for both of us, the bike and me (I'm 52 years old as well) to get a better braking system.

Has anyone else converted their front wheel yet or is there a better way?

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From: BSAC12ver Sent: 20/09/2008 09:31
Hi ozkos6

This is only my opinion and thoughts on the subject.

Yep the C12 brakes are grim by today's standards, over the years I have found it worthwhile to clean the drums out regular, also if you can get old stock new linings (Ferodo?) that come with the rivets (that helped in my case)

I have had a few "moments" regarding braking in time but nothing too hairy as I dont go fast enough because of the brakes.

I also doubt that fitting a disc brake is a good idea? the thing might work well but the wheel might decide to lock up too easy if over applied, reason being the front forks might not respond as quick like a modern bike, the tyre contact with the road is less and so on. (this might be wrong but its what I think could be the case)

Best thing is to play with what you have and try to improve matters, get quick on dropping down through the gearbox helps too as its your best brake! (perhaps not in a real emergency but I find if I need to pull up a bit smart I can quickly drop a gear)



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From: sergentwoodie1 Sent: 20/09/2008 09:36
Oz Mate I have owned my C12 for 52 years I have a standing order with Marks & Sparks for replacement Gents underwear. My worst moment was 6 years ago I had just returned from Germany tour without mishap , next day went to town 1 mile  a van stopped dead over the handlebars  I went but still gripped them from behind no fairing in those days my wedding tackle ended rainbow colours. I have tried to work out a leading shoe arrangement with no success. The rear brake however should be reseasonable !!!!!. If you or anyone comes up with a better idea please put it on board Blow originality! I LOVE MY C12 but I LOVE MY LIFE MORE. Lets all join the BBC , BETTER BRAKES for C's Woodie

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From: camman3 Sent: 20/09/2008 10:28
I was advised a long time ago to fit the soft, green in colour, brake lining material that is used on milk floats (slow but heavy, a bit like C's!).
Just by chance I found a set of shoes on ebay fitted with these linings, and I estimate they improoved braking by at least 25%., the down side is they will wear faster.
The trouble is, I cant find reciept to tell you where to go for them! I will keep looking, but I would have thought some of the other main suppliers must be aware of this and supply them.

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From: sergentwoodie1 Sent: 20/09/2008 10:33
Just to add , I was remembering as I walked Beeza my Jack Russell, I asked the chap who I collected all this C stuff from, " Why did you sell your imaculate C12?" one word answer the "BRAKES" unfortunatly with modern day road users , not only 4 wheels may I add Modern motorcyclists rely all the time on their superb brakes in town traffic one just has'nt got a chance to change down , when I came off I don't think I had even reached the levers. Safe rideing everyone.Woodie

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From: camman3 Sent: 20/09/2008 10:51
By a strange coincedence Woodie, we are just back from walking a pack of five "boarding" dogs, a Lab and four Westies...oh what fun
Every one of them have better brakes than a C!, but they were all  just as unruley and stubborn as us owners!
I know what you mean about the underpants, I.m certain I become invisible when entering the Highcliffe area. More sunshine promised for tommorow, so out on reconnisence (spelling!) run.

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From: ximong8 Sent: 20/09/2008 11:01
For all UK based C owners you could try

Alistair Hilaby Motorcycles in Darwin, Lancashire. 01254 705682.

If you get the recorded message – leave your name and number after it and he will get back to you.

Last time I talked to him, he said the milk float linings greatly improve the breaking of his Triumphs and I think he fits as standard to his restorations.


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From: fredbare7 Sent: 20/09/2008 14:24
My C12 front brake is dangerous. I think I only got an MOT because the
 examiner thought I hadn't long to live in any case. How can you anticipate
an emergency stop, especially when your reaction times are slowing down?
A 7" brake should work. No one could design a brake that bad. I am
trying to achieve 'adequate', to this end I  got a spare pair of brake shoes,with the intention of fitting some better linings, but since they have some good
 ferodo (light green) already fitted, I will try those first. I am concerned that
 the brake cam is 'sloppy' in it's housing. Not wear, just seems made that way.
 All else, including cable etc. seems good. Twin leading shoes would be the
 perfect anwer,but that is an engineering job, well beyond me, but I would
 willingly buy a kit if available. What is a good grease to use on the brake
 parts? I know I only need smear. Jim

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From: chaterlea25 Sent: 20/09/2008 16:36
Hi  All,
Careful setting up of the brakes is critical to performance, the Fulcrum opposite the cam should be loosened and tightened again with the brake applied likewise the wheel spindle.
I put my beliefs in setting up these in a previous mail some months ago
I use the softest non woven linings from Supreme Motorcycles, oversize linings are then turned  to size after fitting to the brakeplate and shimming out the cam 0.010 each side to allow clearance when the shim is removed.
I have done this on all my bikes and with a 7in BSA brake on my Ariel HT5 I can squeal the front tyre!!
When I previously posted I offered an 8in BSA hub to the group, this is from an early Gold Flash or M21, this uses the same spindle as a C12 (stepped) and would fit in without fork mods, I do not have the brakeplate or shoes unfortunately.
Early A65's used a cast iron version of this hub with slightly wider shoes, I have fitted one of these instead of the above hub on my Super Rocket
there are a couple of pics of the SR here, just after I had got it on the road in 2002
It has a Taylor Dow brake plate 
All the spaces above are _ when I typed it in it automatically underlined everything??????
Good Luck
John O Regan

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From: BSAC12ver Sent: 20/09/2008 18:33
Hi Jim
I use a smear of copper grease except on the spindle where I just use 3in1 or engine oil (probabl;y wrong but I have used it for 18 years and its been ok)



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From: bsa_C11G Sent: 21/09/2008 02:33
John hit it in one.
The way to get them to work properly is setting them up correctly.
The bad part is this usually means doing all yourself as 99.99999999999999999999999999999999999999999999999 % of break specalists do not have the foggiest idea of how to machine pads for brakes that do not have a vacum power assist unit adding several tons/ sqinch to the pad area.
1) softest linning you can find. There are some really soft sticky ones used by classic racers.
2) wear of just one thou of ovality in the handlebar base looses nearly .5% of the applied breaking force & I have seen some with 1/4" of movement at the fulcrum pin.
3) wear in any fulcrum point robs a lot of breaking pressure so replace build up & regrind any oval holes, particularly in the backing plate.
4) lubrication, particularly of the cable. The only product I use now days is called "Tri-Lube" , it comes from push bike shops & is what the racers use to lube their gear change cables. It is not cheap, a small 2oz bottle with cost you about the same as 1 hour in a hospital bed.
5) Brake cams. Never seen a good one in use. They all wear very quickly. Drag them out, off to the welders get them hardfaced then polished mirror finish & if the drums are worn get them hard faced a bit bigger to suit your drums, this will cost you about 10 minutes in a hospital bed & save you 10 hours in accident & emergency unit.
6) Cable routing. Over the years cables seem to be getting shorter they must be using the same ruler that my tailor uses cause every year my pants seem to be getting smaller too.
If you can not push & pull the inner its full length with almost no effort or perceptable friction grabbing you need to route your cables better even if this means buying longer ones & cutting them down to size .
7) While you are looking at the cables, they twist when you pull on them . That is why one end has a ball type fitting, so that ( in theory) the cable can rotate freely under pressure. Usually it is the engine end and usually they are totally mangled from years of abuse . I always fit free floating drums to the bar end. Not only dose this mean that you virtually will never replace a broken brake ( or clutch) cable again, it also means that insted of trying to break the cable, you precious broke effort is going to the wheels trying to break your speed.

Little by little inch by inch, you can make the almost standard system capable of locking the front wheel

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From: BSAC12ver Sent: 21/09/2008 09:28

Excellent reply mate, and you are spot on about the cables being shorter, I ended up making my own front brake cable as it was too short (as supplied to me at the Kempton AJ) I was unable to put the brake lever at the "best" angle, when I made the longer cable it really helped my brakes.



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From: fredbare7 Sent: 21/09/2008 12:47
Good imput from all. Now it's a matter of checking it  all out and doing it
 before it's too late. Jim

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From: 1949enfield Sent: 22/09/2008 14:23
A number of questions still exist. Where does one find the correct cam profile for the brake cam ? No one mentioned that different manufacturers specified different pivot positions on the levers fitted which changes the leverage, longer brake arms can also help. As the light 7" brake from a b40 can be made to fit surely this is the way to go , the increase in diameter will mean a better brake even if everything else needs attention. Graham

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From: fredbare7 Sent: 22/09/2008 20:14
Graham,  My brake cam will turn through 180 degrees and give you a new
 set! Although there doesn't seem to be any wear. Unless you are thinking
of entirely new profile! Also my handlerbars and levers are all in one
and original, but there is some play on the pivot, which I can correct.
I'll see how I get on with the general advice given to start with , but a bigger
and  better brake would ideal, as would  more leverage.  Jim

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From: 1949enfield Sent: 22/09/2008 22:12
I must admit I have never seen a worn brake cam though aI have seen a few attacked by an angle grinder for some reason, as for handlebar levers,as a callow youth ,I tended to throw away the original parts and fit bright shiney parts . I once had a gp5 with twin leading shoes which was very simple .The brake shoe pivot pin was replaced with a second cam and the shoes machined flat at the pivot end . This worked very well and if someone has a spare brake plate should be easy to reproduce though there must be a reason why production tls arrangements use shortened shoes and two pivots . Graham

Offline AdminPete

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Re: BSA braking
« Reply #1 on: December 07, 2008, 12:32:20 pm »
From: fredbare7 Sent: 22/09/2008 22:48
Graham,  I was wrong when I said turning the cam gave a new lease of
 life. It doesn't, just swops positon on the brake shoes, but you do have
 a couple of spares to look at!  I'll keep at it.  Jim.

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From: C10Stiles Sent: 23/09/2008 07:32
Hi All,
Next time you go and get your bike MOT'd note down the readings.
My C10 with standard (old shoes) got 50 Nm for the front (not locked up, or is it ABS? Absolutly Blody Silly) any more and the break cable snaps. The rear got 75 Nm, again not locked up.
The chap at the MOT station said that quite a few modern bikes can't even match that!. Having had a bus pull out in front of me (him coming towards me) and jaming on both brakesj ust allowed me to get out of the way!. i know what it feels like!!!.
I may be missing the point but it is no good trying to compare modern machines, designed for modern times, with machines made 50+ years ago. You must ride to the conditions at the time and if that means extra breaking distance or less speed then so be it!.