My wife kindly bought me (the late) Mick Hemmings DVD on Brakes , Wheels and Forks and, as usual with Mick, he suggests improvements.
One is to the Rear Brake Assy to stop it trying to twist when the brake is applied. I know this has been discussed but cannot find it on the forum / NOC website.
It looks to me as though (Domi' paper parts book) p36, fig 28, rear brake cam bearing and nut have to be removed.
Commando parts to use:
060701 cam bearing and stay
060329 locknut
060704 spring
Will Comm' Spacer 060334 simply replace the Domi' one or will a specific spacer have to be machined to suit?
Any help appreciated
Before getting complicated,…
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Does it need it?
The rear brake just functions to keep the back wheel behind the front one. If you have a decent front brake, the rear brake in practice does very little. Making it better would just induce lock-ups.
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Hi Gordon, Perhaps living in…
Hi Gordon, Perhaps living in the wooly wilderness you dont need brakes !, Down here a good rear brake and a fast downshift is a lifesaver when you get a daily fright from the loonies we have. I am building a PR 650 and that will need an uprated brake to work with the lower leverage rear set layout.
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Rear Brake
Back in the 1960's John Tickle produced a Norton alloy rear brake assembly that was thicker and stronger than the metal factory one.
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650 Rear Brake
I'm with Gordon - I like to ride my 650 quickly, and for me, the only time the rear gets any real work to do is when its wet or slippery.
The 'Old Rule' used to be 75% front, 25% rear - nowadays it is more like 90% front 10% rear in normal riding, town, country or motorway. I would look at seeing what needs improving at the front before worrying about the rear one.
However, David mentions the 'upward' or 'downward' facing actuating arm, and I will say the braking was better with the downward arm - I had to go to the 'upward' arm as I have non standard silencers and the lower arm clashed, but it is still possible to lock the rear wheel if you try.
If you do have the 'up' arm, I can let you have my old 'down' one and see if it helps you.
Regards,
George
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Hi George , the exhausts…
Hi George , the exhausts will be raised so probably a down lever will have room. Its all about repeating what was done in the early 60's . I'm sure the manx type rearsets wont provide much leverage at all with the short pedals .
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For Robert
As you are building a cafe racer (hopefully not a modern hipster one with tractor tyres and a plank for a seat!) you need a bigger front brake for style as well as performance. Pic is of mine and renders rear brake relatively unimportant.
As to rearsets and clip ons, I hope your back will still allow it!
Regards,
George
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Sadly thats not anything…
Sadly thats not anything like what was used back then, not allowed . The word is Production Racer. That means what you could get from the dealer at that time. The brakes availiable were SLS 8* drums . Which is why you needed a back brake AND engine braking. Whats the point of a replica if its not?.
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Strengthen Rear Brake Plate Assy Dom, 650SS
Hi David
Mine is the upward facing lever.
Hi Gordon
Sadly self-preservation demands improving my brakes. When I fitted the TLS Front from a Commando I intended a gentle ride out into country roads to try it and see whether I'd got the hang of adjusting it. Didn't get 1/4 mile from home before a lunatic cut accross 2 lanes carved me up and disapeared down a side road. The TLS F brake WAS set up ok (phew!!).
Hi George
You and Gordon are obviously Etoire Bugatti fans ("I make my cars to go, not to stop...")
Thanks for the offer of the downward lever; sadly there's not enough clearance.
Hi Robert
You obviously live in a similar road environment to me. There's no "relaxing".
Hi Anthony
Yes John Tickle produced some great parts.
Thinking Outside The Box;
Does anyone of you have a Commando with drum rear brake fitted with the Cam Bearing and Stay (060701) who can measure the thickness of the arm over the rear axle? I'll be able to work back from that how wide a spacer I'll require.
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spacer 10mm
Spacer is 10mm plus arm is another 3mm.
Will try to add pic with ruler, dimension slightly more as assembly not nipped up.
Regards Martin
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issues with new bits
Forgot to mention this, but once replaced cam Bush and arm as mine was very sloppy/worn, this made brake very ineffective as old shoes were not worn evenly and not enough float in the cam to apply both shoes. Only trailing one as less worn doing anything. So be prepared if you fit new cam Bush and arm, either new shoes or if from Yorkshire swap old ones round on backplate while it is apart.
Regards Martin
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Stronger Rear Brake Plate
Hi Martin
Much appreciated.
The pic' makes sense now.
You know a Yorkshireman is "a Scot with all
the goodness taken out"? (or was it the other way?)
Many thanks.
Tim
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Alloy Rear Brake Plate
The photo shows the alloy rear brake plate for my 650 Cafe Racer. The plate takes standard size Norton 7" rear shoes and has the mounting pin for a torque arm as fitted to early 1950s Dominators or the 'go-faster' (Manx?) swinging arm. The spare chunk on top is the optional location pin for the swinging arm set-up which slides into a lug on the later Wideline or all Slimline arms.
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Tim - As Tony says, John…
Tim - As Tony says, John Tickle produced solid dural brake-plates for both types of swinging arms. I had one on my Domiracer for some years and you would not distort it - at least not by braking. They were all machined and oven-ready - just transfer the shoes etc then ride and forget. It was rigid and had better heat dissipation. The JT part nos were LS3/1 (Std) and LS3/2 (Toque arm). I have seen a few around the jumble circuit. Lots of the Triton fraternity bought them. When fitting any brake into the later swinging arm make sure that the locator is not a loose slide fit and for all older brake plates if the bush is loose on the cam shaft it will sadly move allowing the plate to twist. The Commando rear brake performed better than the 650SS when the extras were added but it was heavier. Good luck, Howard
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Stronger Rear Brake Plate
Hi Phil and Howard
Thanks for your input.
I'll keep looking for the John T' alloy rear brake.
In the meantime have got the Comm' parts to fit.
Stay safe
Tim
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Before getting complicated, do you have the earlier downward facing lever? It fits closer to the backplate.