Clutch rubbers

acotrel · Nov 16, 2022

I came back to Benalla from holiday in North Queensland a week ago. so now I am not so stuffed in the head. A couple of days ago, I took the clutch off my Seeley and had a look to find the reason I ended-up in trouble putting the cush drive back together. The weather had been hot, and I had walked out in disgust. The cush drive is another product from Bastards Incorporated. I was trying to fix it while it was on the mainshaft. It obviously needs to put together on a flat surface, so the centre of the load distributer stays located. There is one thing I cannot remember - I think the cush rubbers need to be lubricated when they are being inserted - methylated spirits or brake fluid - which ?
The clutch is the early type - not Commando.

texasSlick · Nov 16, 2022

I use brake fluid. I am able to insert the rubbers on the mainshaft. However, I made a tool for the purpose. It can be done on a bench, but you still need a tool to twrist the hub while simultaneously counter-torquing the shaft.

My tool was made from several old clutch plates...... see post #16

https://www.accessnorton.com/NortonCommando/tools-you-have-made-to-maintain-your-norton-2021.32308/

Slick

acotrel · Nov 17, 2022

It sounds as though a claw hammer might be the go, I am fairly certain the clutch is pre-Commando Norton. I am used to Triumph clutches which are not made of so many parts. The cush hub is tightened onto the mainshaft and the outer is held forward by the clutch springs and the pressure plate pushing against the stack of friction and plain plates. Seems a bit weird to me. It came to me on a Norton box, which had been used in a Jawa Grass Track bike.
Thanks for confirming the use of brake fluid to slide the rubbers in. I would probably be facing a bigger struggle without that info. I was going to use metho.

Schwany · Nov 17, 2022

What is the advantage of using brake fluid? It'll get contaminated with whatever oil is put in the primary eventually. Not supposed to but it can. Wouldn't ATF work in a pinch.

Babble section: When I was 24 years old putting the rubbers in the AMC 3 spring pre-Commando clutch dry was not that difficult. Not sure exactly how I did it, but I was a lot stronger then. Now everything is more difficult if it requires excessive hand strength.

I like that tool Slick. I'll have to make one. My rubbers are probably hard as stone or pure goop by now. When I replaced them in the 70's they were mush. Clutch frictions and steels and more teeth on the engine sprocket are on the winter project list.

By the way, I thought I had my act together using 0-20 synthetic oil in my primary. Mostly because I had a bunch. Never do that. It worked great until I unleashed a couple more HP sooner in the power delivery. The clutch slipped a lot. When it first happened, I looked in the rear view mirror to see if I was making white smoke frying the rear tire. Nope, just a slipping clutch. ATF does seem to hold up better with a old wet clutch.

Fast Eddie · Nov 17, 2022

Doesn’t really matter what kind or grade of oil you use, but it has to be wet clutch compatible otherwise it is highly likely to induce slip with a capable motor that’s used well.

Schwany · Nov 17, 2022

Fast Eddie said:
Doesn’t really matter what kind or grade of oil you use, but it has to be wet clutch compatible otherwise it is highly likely to induce slip with a capable motor that’s used well.

It was a synthetic 0-20 Mobile 1 experiment in my AMC 3 spring clutch. It did not slip with the ATF I was running in it previously.

I don't have any experience with motorcycle oils that are supposed to work with wet clutches in my Norton primary. I might go get some to see if a quart of oil is really worth $10US, but the weight of most of them is a bit on the heavy side with Surflex clutch frictions and dimpled steels IMO, and freeing up my clutch is a PITA unless I remember to do it after a ride and just before the clutch is cooled down again. Then it frees up easy on next cold start.

acotrel · Nov 17, 2022

My clutch is out in the air. A single row chain which is not in an oil bath will last a very long time under racing conditions, if it is given a squirt of chain lube now and then. But I remember, when rebuilding a cush drive , you need to lubricate the rubbers to get them into the hub. Oil might affect the rubber and turn it into mush. The ones that are already in there have gone very hard. But they were probably always dry.

Alan L · Nov 17, 2022

acotrel said:
I came back to Benalla from holiday in North Queensland a week ago. so now I am not so stuffed in the head. A couple of days ago, I took the clutch off my Seeley and had a look to find the reason I ended-up in trouble putting the cush drive back together. The weather had been hot, and I had walked out in disgust. The cush drive is another product from Bastards Incorporated. I was trying to fix it while it was on the mainshaft. It obviously needs to put together on a flat surface, so the centre of the load distributer stays located. There is one thing I cannot remember - I think the cush rubbers need to be lubricated when they are being inserted - methylated spirits or brake fluid - which ?
The clutch is the early type - not Commando.

Hi,
How are you enduring the floods?

ashman · Nov 17, 2022

What about a little bit of rubber grease, just enough to get them in will also look after the rubbers.

texasSlick · Nov 17, 2022

Schwany said:
What is the advantage of using brake fluid? It'll get contaminated with whatever oil is put in the primary eventually. Not supposed to but it can. Wouldn't ATF work in a pinch.

Babble section: When I was 24 years old putting the rubbers in the AMC 3 spring pre-Commando clutch dry was not that difficult. Not sure exactly how I did it, but I was a lot stronger then. Now everything is more difficult if it requires excessive hand strength.

I like that tool Slick. I'll have to make one. My rubbers are probably hard as stone or pure goop by now. When I replaced them in the 70's they were mush. Clutch frictions and steels and more teeth on the engine sprocket are on the winter project list.

By the way, I thought I had my act together using 0-20 synthetic oil in my primary. Mostly because I had a bunch. Never do that. It worked great until I unleashed a couple more HP sooner in the power delivery. The clutch slipped a lot. When it first happened, I looked in the rear view mirror to see if I was making white smoke frying the rear tire. Nope, just a slipping clutch. ATF does seem to hold up better with a old wet clutch.

Brake fluid does not make rubber "gummy". Neither does ATF, so you are correct that it might work in a pinch.

I found my rubbers had become gummy after using 50W in my primary in the first few years of my Atlas ownership. Oil had migrated into the hub and fouled the rubbers. I now use type F ATF.

According to SAE data, ATF gives 35% more coefficient of friction than oil. That can stop a slipping clutch, or allow one to get by with unloading the spring pressure a half turn or two, resulting in less lever pull.

Slick

Schwany · Nov 18, 2022

texasSlick said:
Brake fluid does not make rubber "gummy". Neither does ATF, so you are correct that it might work in a pinch.

I found my rubbers had become gummy after using 50W in my primary in the first few years of my Atlas ownership. Oil had migrated into the hub and fouled the rubbers. I now use type F ATF.

According to SAE data, ATF gives 35% more coefficient of friction than oil. That can stop a slipping clutch, or allow one to get by with unloading the spring pressure a half turn or two, resulting in less lever pull.

Slick

Brake fluid I wouldn't use, but good to know.

Even with ATF I can't get away with backing off the clutch spring adjusters. I've tried a few times. I have to add a turn. Would be nice if I could back the springs off. If my motor was bone stock with 30mm Amals on it, I probably could back the springs off.

acotrel · Nov 18, 2022

Fixed it, Once it was off the bike and on a flat surface, it was easy. There was an alignment problem - the bit in the centre had moved forward and could not go back All sweet and lovely now.
Fixing a Norton can be difficult if you don't play cricket.

Clutch rubbers

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