650SS rear brake query

Hi Tony,

For one year, I think 1961, Norton fitted large diameter silencers for the US market and the normal rod/lever would not fit so a lever which pointed upwards and with a larger crank was fitted so that the rod would not foul the LH silencer. They must have had lots of these extra off-set rear brake levers made and they carried on fitting them although the large silencers were discontinued. It is a very common modification to fit an earlier type lever as they were more efficient and they look better,

Regards, Rob.

Attached photoshows early Dominator (and other early twin models) rear brake plate and associated bits. The most noteable difference is the plate has an anchor rod which ties it to a position nearer the swinging arm pivot. The later plates had a stud which slotted into the bottom suspension lug on the left side.

If your set up is reasonably efficient and good enough for an MoT, then I would leave it as is. Only the purists are going to moan and groan.

Attachments
pre-1958-style-rear-brake-jpg

Robert -that's the best explanation I've seen for the changed lever - there was a thread on this same topic a few weeks ago.

The earlier lever that Tony has should be better as it has less tendency to bend the backplate outwards. There's nothing to be gained that I can see by changing to the upper, outwards-extended lever - and something to be lost if the back plate flexes more.

Previously robert_gittins wrote:

Hi Tony,

For one year, I think 1961, Norton fitted large diameter silencers for the US market and the normal rod/lever would not fit so a lever which pointed upwards and with a larger crank was fitted so that the rod would not foul the LH silencer. They must have had lots of these extra off-set rear brake levers made and they carried on fitting them although the large silencers were discontinued. It is a very common modification to fit an earlier type lever as they were more efficient and they look better,

Regards, Rob.

hello thinking only gets you in to trouble. you need to know what your writing on this site. The 1961 Machine your on about ,I have one and they were made for less than 10 months . as they were expensive to build. The lager silencers with seam down the side, were made in house by Norton craftsmen. and are now extremely hard to find, As there as not been any after market ones made. But having said this on my Machine the Rear brake lever points up ward and gives and very good braking power .and my 1954 Dominator 88 is the same as it was a export model and was raced at Pebble Beach with some wins too its good name . but now rebuilt back to standard trim with some tweak to the engine , so having the brake lever up or down dose not matter that much as long as the thing works good and is very functional . yours anna j

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picture-418-jpg

Anna - possibly the differences between individual bikes are more than the differences between brake lever types - but the outwards lever puts a much more eccentric load into the backplate so the pivot bearing pressures are bigger and there will be more friction. So like for like the upwards lever will be less efficient...and the eccentric forces tend to bend the backplate. Eccentric loads are always best avoided where possible.

So we have the Manxman to blame for this styling change? Phil's photo shows the downwards lever (with anchor rod and external spring) on an early Dommie. The backplate in his picture is pretty much identical to a prewar bike - except that the prewar bikes have the upwards lever. But that was necessary so as to avoid the drop down rear stand. And the lever doesn't stick out very far because it does not need to avoid a suspension unit. So when suspension arrived they pointed the lever downwards.

And the featherbed Manx had downwards levers...

Previously David Cooper wrote:

Anna - possibly the differences between individual bikes are more than the differences between brake lever types - but the outwards lever puts a much more eccentric load into the backplate so the pivot bearing pressures are bigger and there will be more friction. So like for like the upwards lever will be less efficient...and the eccentric forces tend to bend the backplate. Eccentric loads are always best avoided where possible.

So we have the Manxman to blame for this styling change? Phil's photo shows the downwards lever (with anchor rod and external spring) on an early Dommie. The backplate in his picture is pretty much identical to a prewar bike - except that the prewar bikes have the upwards lever. But that was necessary so as to avoid the drop down rear stand. And the lever doesn't stick out very far because it does not need to avoid a suspension unit. So when suspension arrived they pointed the lever downwards.And the featherbed Manx had downwards levers...

So did the standard '54 Dominator 88.

Previously David Cooper wrote:

Anna - possibly the differences between individual bikes are more than the differences between brake lever types - but the outwards lever puts a much more eccentric load into the backplate so the pivot bearing pressures are bigger and there will be more friction. So like for like the upwards lever will be less efficient...and the eccentric forces tend to bend the backplate. Eccentric loads are always best avoided where possible.

So we have the Manxman to blame for this styling change? Phil's photo shows the downwards lever (with anchor rod and external spring) on an early Dommie. The backplate in his picture is pretty much identical to a prewar bike - except that the prewar bikes have the upwards lever. But that was necessary so as to avoid the drop down rear stand. And the lever doesn't stick out very far because it does not need to avoid a suspension unit. So when suspension arrived they pointed the lever downwards.

And the featherbed Manx had downwards levers...

well my 1954 model88 are the same pointing up as this was a export bike that come back. and I have very good rear brakes so I cannot see How this will Have Less Effect you have more of a straight pull when the arm is up ward . you have less effect when the arm is down ward as it as to pull to 180 degrees as the rods is at a angel as you use your foot on the brake peddle there less movement and you pulling against a big spring as well on the back plate. were on my bike there is no big spring. it moves more easily and give you a good stopper and you do not have to blame the manxman for the design change . as the 1954 model 88 I have its the same. and works better . And the machine in Phil Hannah picture is a Nomad if you look at it right

in 1957 the full width hub got a revised backplate lever & cam. For 1961 the 650cc got a new lever, pointing upwards with a considerable offset. According to Bacon, there were 2 reasons for this: 1) to clear the large diameter silencers fitted to U.S. machines & 2) to enable the operating rod to clear the damper on its way to the lever. The silencer soon went away, but not the lever, which became standard fitment in 1964 & is best changed to the older type lever, or the later Commando type (part #067755). The backplate was again modified in 1966, and futher improvement can be made to stiffen it by using the Commando cam-spindle bush (part #060701), a narrower cover plate spacer (# 060334), and lever return spring ( 060704). This is also a method of repairing a worn cam lever bush.

Skip Brolund

I agree totally with everyone........as usual. Even with the people who disagree with each other. Like many Norton bits, this rear brake back plate is a case where there are quite a few variations but most will fit and do a good job if adapted correctly. Timing coversare another goodexample.

The point Skip makes about the later off-set brake lever is very valid. It is a very poor answer to a problem that existed for a only a short time and really should have been binnedalong withthe fat Export silencers. Its geometry often results in the brake plate starting to bend before enoughforce arrives at the shoes, which makes it far less efficient than the previous underslung lever. I can only assume that the Slimline frame with itsmore rearward footrest position was the reason why Norton never returned to the better underslung lever. Or perhaps they had crates ofspare off-set levers and just fitted them to get rid of as many as possible.

The rear brake bending problem was well known in the 60s and an 'after-market' solution was the thicker alloy rear plate, which is still available. The Norton factory took the usual 'cheap-skate' solution, with the first Commando,and just fitted an outsidesteel support bracket and a revised off-set lever. This might have worked resonably well but for the stretchy cable between the foot pedal and the brake lever which kills any feed-back.

For the purists who also spotted the Nomad rear brake plate I posted. It was the only clear photo I could quickly find that was under 1k in size and looked close enough to what was described in the question.

I have attached a photo of a later style Dommie rear brake plate for those people who wishto play 'spot the difference.' Thisone isattached to an alloy rim by somebody who was obviously feeling a bit suicidal. Check out the spoking!!!!

Attachments
Naff%20Spoking%20-%20Alloy%20Rim.jpg

Previously phil_hannam wrote:

I agree totally with everyone........as usual. Even with the people who disagree with each other. Like many Norton bits, this rear brake back plate is a case where there are quite a few variations but most will fit and do a good job if adapted correctly. Timing coversare another goodexample.

The point Skip makes about the later off-set brake lever is very valid. It is a very poor answer to a problem that existed for a only a short time and really should have been binnedalong withthe fat Export silencers. Its geometry often results in the brake plate starting to bend before enoughforce arrives at the shoes, which makes it far less efficient than the previous underslung lever. I can only assume that the Slimline frame with itsmore rearward footrest position was the reason why Norton never returned to the better underslung lever. Or perhaps they had crates ofspare off-set levers and just fitted them to get rid of as many as possible.

The rear brake bending problem was well known in the 60s and an 'after-market' solution was the thicker alloy rear plate, which is still available. The Norton factory took the usual 'cheap-skate' solution, with the first Commando,and just fitted an outsidesteel support bracket and a revised off-set lever. This might have worked resonably well but for the stretchy cable between the foot pedal and the brake lever which kills any feed-back.

For the purists who also spotted the Nomad rear brake plate I posted. It was the only clear photo I could quickly find that was under 1k in size and looked close enough to what was described in the question.

I have attached a photo of a later style Dommie rear brake plate for those people who wishto play 'spot the difference.' Thisone isattached to an alloy rim by somebody who was obviously feeling a bit suicidal. Check out the spoking!!!!

Well You have put the cat among the pigeons Now then Phil If you had and thing to do with Manxman silencer that you would not say in you thread they need to be binned As they are better than any Of the silencer thats ever been fitted too a Norton they do give of a very nice sound too and because they have a long welded bracket on top they fit better to the frame and they look nice too. they have two baffle plates in one inside the other are made from 1.5 mm thick steel And No one have ever made any since Bracebridge street works So there the Original silencer And I have a Original cigar type silencer too they do not have a folded seam at the bottom like the After market ones and there made of 1mm thick steel at the bottom theres welded seam there have a different cone end too , Now my back brake plate dose not bend at all its got a very keen brake and is marginally better than any early brake . and my 1954 dominator as the same brake fitments as the manxman. they work better too . so if it works good theres no need to try fix it. yours anna j

Hi Phil, I wasn't going to say anythig, but since you let the cat out of the bag, I loved the Nomad photo!! I saw the "squished" swing arm legs to allow for the rear tire & I got to looking closer & saw the welded on height spacers on the center stand & new it had to me a Nomad !! Thanks for that, it made my day. As to photos here on this site, I still like to use photobucket, its free & you can use as large a photo as you wish. Thats quite a spoke job, I'll bet a wheel show would buy that just to hang in the shop as a conversation piece!

Unusual - but why dangerous?

There's a fashion for odd spoke patterns among some cyclists but as long as they are fully symmetrical there's precious little to choose between them. Fully radial spokes aren't a good idea where drum brakes or the drive sprockets apply torque to the hub. But as long as the rim dimples allow it (maybe they don't properly), what's the problem with the illustrated wheel? Lots of old bikes are mostly conversation pieces. Lets seemore spoke patterns!

Previously David Cooper wrote:

Unusual - but why dangerous?

There's a fashion for odd spoke patterns among some cyclists but as long as they are fully symmetrical there's precious little to choose between them. Fully radial spokes aren't a good idea where drum brakes or the drive sprockets apply torque to the hub. But as long as the rim dimples allow it (maybe they don't properly), what's the problem with the illustrated wheel? Lots of old bikes are mostly conversation pieces. Lets seemore spoke patterns!

Hello On Norton Motorcycles There Are More than just One spoke patents but this all depends what the machine is going to be used for and the size of engine right from early days spoke patents have changed from machine too machine. and not many people seam to notes this. until they need to change the rim. so don't get the tin snips out to cut the spokes. the wheel builder will need to know what patent it had. is best just to leave well alone . for the wheel builder. to do . unless you know what your doing and have the experience in wheel building, like I have. Yours Anna J .

Previously anna jeannette Dixon wrote:

Previously phil_hannam wrote:

I agree totally with everyone........as usual. Even with the people who disagree with each other. Like many Norton bits, this rear brake back plate is a case where there are quite a few variations but most will fit and do a good job if adapted correctly. Timing coversare another goodexample.

The point Skip makes about the later off-set brake lever is very valid. It is a very poor answer to a problem that existed for a only a short time and really should have been binnedalong withthe fat Export silencers. Its geometry often results in the brake plate starting to bend before enoughforce arrives at the shoes, which makes it far less efficient than the previous underslung lever. I can only assume that the Slimline frame with itsmore rearward footrest position was the reason why Norton never returned to the better underslung lever. Or perhaps they had crates ofspare off-set levers and just fitted them to get rid of as many as possible.

The rear brake bending problem was well known in the 60s and an 'after-market' solution was the thicker alloy rear plate, which is still available. The Norton factory took the usual 'cheap-skate' solution, with the first Commando,and just fitted an outsidesteel support bracket and a revised off-set lever. This might have worked resonably well but for the stretchy cable between the foot pedal and the brake lever which kills any feed-back.

For the purists who also spotted the Nomad rear brake plate I posted. It was the only clear photo I could quickly find that was under 1k in size and looked close enough to what was described in the question.

I have attached a photo of a later style Dommie rear brake plate for those people who wishto play 'spot the difference.' Thisone isattached to an alloy rim by somebody who was obviously feeling a bit suicidal. Check out the spoking!!!!

Well You have put the cat among the pigeons Now then Phil If you had and thing to do with Manxman silencer that you would not say in you thread they need to be binned As they are better than any Of the silencer thats ever been fitted too a Norton they do give of a very nice sound too and because they have a long welded bracket on top they fit better to the frame and they look nice too. they have two baffle plates in one inside the other are made from 1.5 mm thick steel And No one have ever made any since Bracebridge street works So there the Original silencer And I have a Original cigar type silencer too they do not have a folded seam at the bottom like the After market ones and there made of 1mm thick steel at the bottom theres welded seam there have a different cone end too , Now my back brake plate dose not bend at all its got a very keen brake and is marginally better than any early brake . and my 1954 dominator as the same brake fitments as the manxman. they work better too . so if it works good theres no need to try fix it. yours anna j

Hello My Manxman has just past it M.O.T to day and the rear Brake had More braking power than the front one . at 89kg the rear brake 92kg on the brake meter so thats 181kg on both brakes the bike weight 200kg in total and thats wet , or with fuel and oil. so that was interesting to know. yours anna j

But surely the function of a back brake is just to keep the wheels in line whilst the front one does all the serious stopping? Or am I missing something. So while it is of course a good thing to have a properly engineered back brake, it doesn't have to be particularly effective.The back brake is operated by a hefty boot, makingitall too easy for it to be too effective, locking the back wheel. The trick is to have a front brake that can do the job when the input is a comparatively weeny squeeze and a back brake that isn't too fierce when stomped on. Gordon.

Previously David Cooper wrote:

Unusual - but why dangerous?

There's a fashion for odd spoke patterns among some cyclists but as long as they are fully symmetrical there's precious little to choose between them. Fully radial spokes aren't a good idea where drum brakes or the drive sprockets apply torque to the hub. But as long as the rim dimples allow it (maybe they don't properly), what's the problem with the illustrated wheel? Lots of old bikes are mostly conversation pieces. Lets seemore spoke patterns!

I understand for a spoke to work at it's best it needs to be inline with braking and acceleration forces. i.e as close to a 90 degree angle as possible with a line drawn from the wheel spindle to the point where the spoke is attached to the hub. I agree with Phil. The spokes in the photo are nearer 30 degrees, thus offering little resistance to braking and acceleration forces, dodgy.