Discussion in 'Norton Motorcycle Rebuilds' started by springer, Oct 1, 2018.
Start worrying when it doesn’t hold you back.
I dunno, it’s surprising how good a single disc can be on a light bike with modern pads.
If you will look more carefully at the second picture, at Daytona, you will notice that the bike has dual front discs, not single. Rob used either single or dual discs, as seemed appropriate to him at the time. For some tracks the single disc was more than adequate, and significantly lowered unsprung weight, but for others, like Daytona, with heavy braking from very high speeds, he preferred the dual setup. It all worked well for him. He was a regular race winner back then, and won at least one national AHRMA class championship. He eventually got his PhD in Astrophysics, but couldn't stay away from the racing scene. He later became the head of research and development for the ING Renault F1 team, and then moved on to chief scientist and head of R&D for the Mercedes GP Petronas F1 Team. I've lost touch with him, so not sure what he is currently doing, but he was a serious Norton enthusiast back then.
Dave Watson's bike that Gary Thwaites rode to all those championships has a single disc.
Now a triple with a single disc! That's another matter.
Weight is the biggest factor.
Ps single disc on my Nortons
Perhaps if you have aluminium barrels, you only need one disc ? I use two Suzuki high speed steel discs with Lockheed callipers and the old type asbestos pads. It is single finger operation and it has to be like that for short tight circuits. The front brake needs to work instantaneously and strongly without locking. It limits how fast you can ride the bike.
Al, when you say “old type pads” what exactly do you mean?
Pad technology has come on at least as much as everything else in recent years. Pad choice makes a tremendous difference...
Ralph recently took his second disc OFF of his Norton Seeley as he just didn’t need it and preferred the weight reduction. I forgot what pads he’s using though...
I had a Seeley/Norvil twin disc front end on my 750 mk4 with the ( cough) floating discs.
I run my 960 mk2 with a single disc & Lockheed pads from Ken ( Hersham racing) in the paddock.
I tried fa111? Pads as recommended by Cormac Conroy as the all singing all dancing best race pads available. They were brutal. Worried me about using them in the wet!
I thought Lockheed red pads were the bee's knees 20 years ago, they dont come close to the new stuff.
Time moves on, we stick with what we are comfortable with.
The lighter front end works for me.
Back to Springers original post.
I ran a 5 speed Triumph box in my 500 Dommie racer. Good as gold. I ran a Nourish shell (strengthened) Triumph 5 speed with cut down inner & outer cover. It would have been fine but I had the problem that effects Triumphs ie the bush pushing up on the shaft from the third gear. As Eddie said you can now source the 5 speed mainshaft with Norton clutch from Tony Hayward. It is the way to go, although I seem to recall strengthened pre unit shells being sold by someone in historic racing.
Not sure where you would get a Nourish shell from now days. I did a convoluted deal with a friend of Eddie's for a mate who has put a deposit down on a new one, that never looked like arriving from Mr Bushell.
For a street bike standard second hand would work well. Once you go above 750 it becomes a bit iffy.
Chris, did the Bushell case ever materialise ?
The pads on my bike are as old as the hills. I tried using carbon racing pads and found I had no brakes. I think most of the modern pads don't use asbestos. It is an industrial safety thing. I know with car clutches, the change of material made them less effective. I don't ride my bike often enough to wear out the pads. But if I did, then I would probably have a problem finding something as effective.
Al I think you would be staggered at how poor your ‘old as the hills’ pads are vs what you can get today.
After I sold my 500cc Triton back to my friend who had originally built it, he fitted a 5 speed cluster to it, a pair of decent tyres and put it on petrol instead of methanol. I rode it at Winton and it was almost sane - however I still got it sideways in a corner. The gear ratios were a bit wider than when I raced it with the four speed close box. Because the bike was a bit tamer, it did not seem to matter. I could probably ride the bike faster in a race, since it lost it's drama. That Phil Pick mod of moving 2nd and 3rd gears up towards 4th in the five speed box, might give a bit better acceleration.
No casing no refund. Nourish box is behind a Goldie engine on the track.
Al no carbon just new technology they don't wear out as quick as the old pass iether. Quaife gears by the way.
Drag it out of the shed lol you know you want too.
With my front brake, the master cylinder is operating two callipers when it is designed to operate only one. The set-up is about as savage as it can safely be.
There was a ride day at Winton last weekend which I was aiming for, however over the last couple of months I have dropped $8000, so other things have taken priority. In a minute, I will be in a better position so I just have to be patient. I used to be able to go there whenever I chose - times change.
Thank you man for the info!
Eddie, It is not only about the pads. The disc material is extremely important. With a chrome plated disc, my asbestos pads are useless. However with the Suzuki high-speed steel discs they are excellent. I tried modern carbon racing pads with the steel discs and I could not get them to grip. I have a cast iron disc on the rear of my Seeley with a Honda calliper which I must get rid of. Cast iron discs give the best grip, but there are three grades of cast iron - grey cast iron, meehanite and nickel-bearing cast iron. My friend was killed at Bathurst when using discs made from the wrong material - they exploded off the front of the Suzuki RG500 as he braked at the end of Conrod straight. He ended up in the car park with the spectators.
I suggest that if you find a combination of discs and pads which works well, you are lucky. If I had better brakes on my Seeley, I would probably crash every time I used the bike. It stops like hitting a wall - one finger. And I never use the bike on big circuits. I know what savage brakes are like - have you ever locked a drum brake at 100MPH and crashed down the road ? I've done it about three times.
Al, bicycle brakes can be locked up easily, but it doesn’t mean they’d stop a Hyabusa on full chat!
There’s more to ‘good brakes’ than outright lockablity...
Eddie, lockability is a hazard, but you should be able to lock the front brake, if you so choose and do it without crashing. What I need in a front brake is strong smooth stopping power. With my Seeley - any more brake and it would be dangerous. There is a problem which occurs mainly with drum brakes - if they work weakly and you hold them on, the linings heat up and eventually can stick causing the brake to lock and launch you. Disc brakes have no self-servo, so if the linings only work when they are hot, if you get too much braking, you can usually let go. These days, I would never try to race a bike with a drum brake - it is just asking for trouble. In Australia there is one historic class which requires drum brakes, we never put disc-braked bikes in the same races. A person who gets clever with a disc brake can literally kill a guy on a drum-braked bike.
With the NORTON box , you get half way to close ratios ( on the cogs ) and 1st gets to small for the kick start pawl .
With the FOUR SPEED .
Whereas the Triumph box has identical ratios to Norton Close , within a microfarad , AND maintaINS THE kICK sTART
Id assume a similar case on the 5 speeds ?
Something like 20 , 22 & 24 teeth cogs , the 22 being the forst the pawl fits in . Back then, anyway .
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