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Brake arm problem on 650SS

Submitted by jonathan_soons on Fri, 04/09/2015
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Heavy Twins

I put a new rear wheel on my 650SS and then discovered that the brake arm now pointed up instead of down. The brake arm itself is different. It is now more cranked so the brake rod can still reach it but is it the wrong brake for the bike? Is it now a death trap? Here is a picture:

Attachments pilot-jpg

Submitted by david_cooper on Fri, 04/09/2015

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Earlier is on the right and later is on the left. Allegedly changed (maybe around 1964?) because careless riders burnt their fingers on the hot silencer with the early type when adjusting the rod length. I've no idea why they would do such a thing..The bigger offset on the upturned lever is to allow the rod to miss the shock absorber. But the offset allegedly also puts more sideways bending into the backplate. Maybe others may tell us if that's a problem?

Submitted by phil_hannam on Fri, 04/09/2015

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This is almost a no-win situation. The pre-cranked arm is more mechanically efficient whether at the top or bottom of the brake plate pivot. However, fitting one to a Slimline frame creates two potential problems.

It either snags the rear suspension units or the passenger footrest. On my Dommie cafe Racer I wanted brakes that were as good as possible at the back. So I fitted a 2 into 1 exhaust with a right side silencer and did away with the passenger footrest. Success!!!

Submitted by jonathan_soons on Fri, 04/09/2015

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Previously ian_cordes wrote:

I may be missing something here, but can't you try swapping the brake lever arms over?

I'm not fussy over which one I use. I would prefer to use the better one (right one?) now that I know they are both Dominator items.

Submitted by jonathan_soons on Fri, 04/09/2015

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Previously barry_carson wrote:

i dont think they swap the lever at the top if fitted at the bottom ends up to far forward.

Right, I think they are not reversible individually but they seem to be interchangeable.

Submitted by jonathan_soons on Fri, 04/09/2015

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Previously Phil Hannam wrote:

This is almost a no-win situation. The pre-cranked arm is more mechanically efficient whether at the top or bottom of the brake plate pivot. However, fitting one to a Slimline frame creates two potential problems.

It either snags the rear suspension units or the passenger footrest. On my Dommie cafe Racer I wanted brakes that were as good as possible at the back. So I fitted a 2 into 1 exhaust with a right side silencer and did away with the passenger footrest. Success!!!

And which brake arm did you use? Pointing down I suppose.

Submitted by jonathan_soons on Fri, 04/09/2015

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Just to clarify, I don't remember what brake the bike came with. The wheel I just took off is a 19 inch emergency replacement after I crashed the bike in 1973. I brought the bike over to the USA where they only have 18 inch WM3 slimline rear wheels. Hence that odd new wheel but everyone so far is suggesting it is usable.

Submitted by jonathan_soons on Fri, 04/09/2015

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Previously David Cooper wrote:

Earlier is on the right and later is on the left. Allegedly changed (maybe around 1964?) because careless riders burnt their fingers on the hot silencer with the early type when adjusting the rod length. I've no idea why they would do such a thing.. The bigger offset on the upturned lever is to allow the rod to miss the shock absorber. But the offset allegedly also puts more sideways bending into the backplate. Maybe others may tell us if that's a problem.

That settles it then. It is just a later Atlas wheel. I have no problem with that.

Submitted by ian_cordes on Sat, 05/09/2015

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Previously barry_carson wrote:

i dont think they swap the lever at the top if fitted at the bottom ends up to far forward.

Just swap the lever and operating cam; they have to work together, if they did before.

Submitted by david_cooper on Sat, 05/09/2015

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Re: clash with passengers footrest.. my downwards lever passes about 1/2 inch above the passengers footrest when bike is on its stand ( on full rebound).I suppose it is more vulnerable to being trodden on but there has never been any need to remove the rest.

Submitted by Xanna_jeannett… on Sat, 05/09/2015

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Hello to you with insignificant bits of steel call Nortons well my insignificant bit of steel built december 1960 a early Norton Manxman 650 has its rear brake arm pointing up ward , and has never been any trouble at all, your micocosmic bit of space dust , anna J from a far planet Earra

Submitted by jonathan_soons on Sat, 05/09/2015

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Previously anna jeannette Dixon wrote:

Hello to you with insignificant bits of steel call Nortons well my insignificant bit of steel built december 1960 a early Norton Manxman 650 has its rear brake arm pointing up ward , and has never been any trouble at all, your micocosmic bit of space dust , anna J from a far planet Earra

This doesn't seem to be a date-of-manufacture or model specific thing. Unless Anna has a newer rear wheel also.

Submitted by david_cooper on Sat, 05/09/2015

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Bacon's 'Norton Buyers Guide' shows Anna's bike page 71 dated 1961 with upwards lever. Page 70 has a 1960 deluxe with down lever. But the 1961 road test of 88 ss in Motor Cycling has down lever as does the 1961 photo of a 99 ss in his 'Norton Twins'. So it looks like it altered some time in 1961 model year since all the later pics have upwards levers.

Submitted by Xanna_jeannett… on Sat, 05/09/2015

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Previously Jonathan Soons wrote:

Previously anna jeannette Dixon wrote:

Hello to you with insignificant bits of steel call Nortons well my insignificant bit of steel built december 1960 a early Norton Manxman 650 has its rear brake arm pointing up ward , and has never been any trouble at all, your micocosmic bit of space dust , anna J from a far planet Earra

This doesn't seem to be a date-of-manufacture or model specific thing. Unless Anna has a newer rear wheel also.

No its all original with a Wm3 18 inch rear tyre has this were export bike and never sold in the uk until late 1961 the only bikes sold earlier too this was the police model 650 made of the London Met made out of the Norton Manxman these had a larger tank and leg shealds small seat and radio aft of the seat and had 12v electrics and all in police black. they were real bikes for real crime chasers and they alway got there man, they were the fastest and best handling motorcycle the british police ever had at that time, orginal post for 1961 Norton Manxam 650 looks like the rear leaver is pointing upward , look for your selfs this poster would of been made in november 1960 , for the export market, USA the biggest market ,

yours anna j dixon the bio-enterty from Earra !!

Attachments norton_1961_manxman_650_advert-jpg

Submitted by jonathan_soons on Sun, 06/09/2015

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Previously anna jeannette Dixon wrote:

This doesn't seem to be a date-of-manufacture or model specific thing. Unless Anna has a newer rear wheel also.

No its all original with a Wm3 18 inch rear tyre

Then my comment stands and the style change is a mystery.

 


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