Clutch question?

Greetings,

A friend brought me his 70 commando sport, that hasn't ran for 25 years. We got it running, you know the usual, carbs, gas tank, petcocks, and stuck clutch plates. The clutch is extremely hard to pull. We lubed the cable, it didn't help much. We're going to install a new cable. He informed me that he had a different clutch installed years ago, because the stock clutched slipped when he'd get over 100mph (nothing better than good bull shit). Anyway, the clutch that is in the bike has an indexed, first steel plate, indexed with roll pins. I have only worked on my 72 interstate, and triumphs. The parts books list a friction plate first. I have not found a indexed 1st plate listed anywhere. We're going to try the cable fist. I need to change the o ring on the kick start shaft, and I'll investigate actuator when I have that apart as well.

I am wondering if the spring was replaced with the clutch back in the day. He said it was a hard pull back then but it didn't slip. Maybe someone here will know more about what we're dealing with. And perhaps some other things to look for.

Thanks for all replies,
Phil

10drum said:

Anyway, the clutch that is in the bike has an indexed, first steel plate, indexed with roll pins. I have only worked on my 72 interstate, and triumphs. The parts books list a friction plate first. I have not found a indexed 1st plate listed anywhere.

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The early Commando clutch chainwheel had a separate backplate (item 3) secured by roll pins.
An original backplate doesn't have the three rivet holes.

Later clutch chainwheels have the backplate riveted to the drum so whether the clutch has a separate or fixed backplate the first plate fitted is a friction plate.

It probably has the incorrect clearance between the pressure plate and the snap ring. A properly set up Commando clutch is not stiff at all but a lot of them are due to improper (quite possibly original, from the factory) clearance. They are a two-finger pull when correct.

The above mentioned information is proven accurate.
It alowed me to build a no slip, easy pull, no drag, no grab, linear engagement clutch the first time. Thanks, Dave!

Check that the actuating arm hasn't dropped down

And check cable routing. That has a surprising impact on pull.

I had a very stiff clutch, that made my hand painful after a couple of hours. I appear to have sorted it:
1. Good lube of the cable, helped, but didn't solve it;
2. Cleaned the clutch plates and basket. There was a light film of oil on the interface between the diaphragm and the 1st plate. That might have created a surface tension that needed to be broken, before the spring moved, maybe...;
3. Replaced the clutch centre. It was heavily notched, wear from the plates. I couldn't see how this would make any difference to the effort needed to move the diaphragm spring, but thought it needed it and you never know...; and
4. Spent time checking, double checking and triple checking the adjustment. With the cable slackened at the handlebars, I used the point when I could no longer feel movement in the actuator inside the gearbox, as the point to then back off between 1/2 and 3/4 of a turn.
One or more of steps 2 to 4 made the difference. My guess would be proper adjustment most likely made the difference. Now two fingers light. On a ride yesterday, realised I was using the clutch without thinking about it.

MexicoMike said:

It probably has the incorrect clearance between the pressure plate and the snap ring. A properly set up Commando clutch is not stiff at all but a lot of them are due to improper (quite possibly original, from the factory) clearance. They are a two-finger pull when correct.

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I think you have the best explanation. I had those plates in and out a few times, and I was not happy how it went together. We have other things to do to the bike, and I'll pull the plates again. Would the solution be to replace the basket, with a newer style? Mine is a two finger pull

10drum said:

Would the solution be to replace the basket, with a newer style? Mine is a two finger pull

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The stack height probably needs adjusting. The lower the stack height is, the heavier the clutch action will be.

10drum said:

Would the solution be to replace the basket, with a newer style? Mine is a two finger pull

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There would be no point in that as even the later riveted bottom plate is still the roll pin plate modified (so the height is the same)
Even when the roll pin version gets a little loose (not that it really matters) it is simply a matter of replacing the 1/8" (3.175 mm) stock roll pins with 3.5 mm roll pins along with some Loctite as an option.



Something like this, done for a member here most likely.
Good for another 50 years.

Yep - stack height. Old Britts used to sell various thickness steel plates to obtain the proper stack height/easy clutch pull. Maybe somebody else does...

Barnett plates offer the benefit of an alloy host plate, which doesn't destroy the clutch hub.

I am still running the same clutch that has come out of the factory the only thing I have replaced in the 46 years of ownership is the clutch centre about 8 years ago, a new clutch pressure plate and the spring that holds everything in place, still running the same steel and bronze plates and ATF-F in the primary, my clutch has always been a light pull and running the ATF in the primary has stopped any clutch slip, has never suffered the GB oil in the primary, but I do yearly maintenance in my primary and clutch basket whether it needs it or not, I have never check stack height as everything works prefect.
I did run fiber plates for a year then back to the stock plates when I went down the belt drive way and ran a dry primary but went back to the stock set up and primary chain after 2 years and when I need to replace the primary chain next will be a twin chain from the chainman.
You can run the stock steel and bronze plates dry in a belt drive set up but the clutch bites a bit quicker .

Ashley

MexicoMike said:

Yep - stack height. Old Britts used to sell various thickness steel plates to obtain the proper stack height/easy clutch pull. Maybe somebody else does...

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RGM does.