Dominator or Manx cush drive clutch hub center on Commando?

YukoNorton

YukoNorton

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another question about early parts on a Commando...

On my '74 850, the non-standard rear wheel has no cush drive (not changing it) , so,
can I fit an earlier Dominator or Manx clutch hub center with the cush drive with the original Commando clutch basket?
If not, what would it take to have a cush drive in the clutch hub?
 
YukoNorton said:
another question about early parts on a Commando...

On my '74 850, the non-standard rear wheel has no cush drive (not changing it) , so,
can I fit an earlier Dominator or Manx clutch hub center with the cush drive with the original Commando clutch basket?
If not, what would it take to have a cush drive in the clutch hub?
Click to expand...
The first commandos had no cush drive at all
A lot of people don't mind it but I find it a bit harsh especially selecting first gear
I don't believe it's possible to convert a commando clutch to cush drive
I'm happy to be proven wrong?
The easiest course would be to fit a commando cush drive rear wheel
 
I use a Manx type clutch behind my 850 motor with a single row primary chain and Jawa speedway engine sprockets. I have made the splined adaptor to allow the engine sprockets to float and be quick-change. There is a quarter of an inch difference in the length of the gearbox mainshaft - must be coped with. You might be able to recess the back of the Manx clutch, but I doublt it. Alternatively - you could fit a Dominartor main shaft.
 
If you replace the transmission mainshaft with a Dominator or Atlas shaft, you can then fit the AMC clutch with its cush hub.

If you are ingenious enough, you might fit the AMC clutch over the Commando mainshaft. I did the inverse, fitting the Commando clutch over the Atlas mainshaft, but do not remember the intricate details. It is worth a try, before resorting to replacing the mainshaft. I think you will find the AMC clutch has less mass, and is more enjoyable. Eventually i changed the Commando clutch back to the AMC because I missed the cush drive, and because I did not like the increased inertia of the Commando clutch.

Slick
 
Another thing worth mentioning is that the clutch operating lever inside the box is different. So a dommie clutch will need a replacement if you want a light clutch. Even more with a Manx clutch which needs less movement as it was designed for the laydown gearbox.
A lighter clutch can also be achieved by changing to a clutch lever with different pivot to cable nipple centre distance.
 
Is the mechanism in a dommie box different from the one in the Commando ? The 3 speed close box I was using did not come from a Commando. I thought they were the same.
 
If going to single row primary chain to get an AMC clutch and cush hub, the AMC clutch sprocket is not going to line up with the engine sprocket using a Commando gearbox mainshaft. As Al mentioned the Commando mainshaft moves the old 3 spring AMC clutch out 1/4". The AMC clutch does not butt up to the Commando circlip at the rear of the splines on the mainshaft. It butts up against the step at the front of the splines on the mainshaft. You would have to use a pre-Commando mainshaft of some flavor. There are several to choose from.

The old AMC clutch fully assembled in stock form is heavy. The cush in the AMC hub is not that great of an improvement over having no cush.

Short answer is No you cannot just use the AMC clutch hub without redesigning the Commando clutch basket, and manufacturing one off friction and steel clutch plates.

A lighter weight aftermarket Commando belt clutch without cush wouldn't be as violent going into 1st. As far as upshifting and downshifting once underway without a cush clutch hub goes, there is no difference as far as I can tell. My AMC clutch is in a box on the shelf. I'm using a NEB clutch that weighs half as much and does not have a cush hub. My rear wheel hub is not cush either. Use your foot to roll a little forward when shifting into 1st and most of the clunk goes away. Desperate times call for desperate measures. :)
 
YukoNorton said:
I saw that Pender has the cush-drive wheel hub; nice.
My rear wheel is a mag type, no threaded spokes.
Click to expand...
You could still have a cush drive. Take a look at Steve Maney's cush drive. It's within the sprocket carrier.
Mind you, there will be some tayloring needed, the solution doesn't come cheap, but it's doable. Probably the cheapest solution of all proposals.

- Knut
 
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Another possibility is replacing the Commando clutch with a Triumph triplex clutch, as used on the T140. Their design has a cush drive, very similar to AMC's clutch hub (I suspect they copied the design), it has triplex chain of the same dimension as the Commando as well (3/8"p x 7/32"w). Number of teeth is just marginally different, so gear ratio will not change much (58T vs. 57T). The Commando's front sprocket should be retained. I don't expect a clearance problem in the chaincase, but this would have to be verified of course.
Aligning the drive and producing a clutch centre fitting the splines of the long Commando mainshaft is a task that has to be overcome, but I rate this a realistic option. No quick and cheap solution though.

- Knut
 
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YukoNorton said:
Thanks for your replies, ideas, information and discussion.
It looks like I will continue to be mindful and ride my 850 being gentle on the gearbox/drivetrain...ride it like I don't have a cush drive...because I don't.
Click to expand...
If you're not prepared to spend money on an improvement, why bring up the the discussion? There is no magic wand when it comes to engineering.

- Knut
 
mdt-son said:
Another possibility is replacing the Commando clutch with a Triumph triplex clutch, as used on the T140. Their design has a cush drive, very similar to AMC's clutch hub (I suspect they copied the design), it has triplex chain of the same dimension as the Commando as well (3/8"p x 7/32"w). Number of teeth is just marginally different, so gear ratio will not change much (58T vs. 57T). The Commando's front sprocket should be retained. I don't expect a clearance problem in the chaincase, but this would have to be verified of course.
Aligning the drive and producing a clutch centre fitting the splines of the long Commando mainshaft is a task that has to be overcome, but I rate this a realistic option. No quick and cheap solution though.

- Knut
Click to expand...
Whilst I agree this should be a possible engineering alternative the t140 clutch is vastly inferior compared to a commando clutch
 
Why not just buy a commando hub assembly with the cush drive
And lace your existing rim onto it
You can re use the spokes
Do the job yourself
 
baz said:
Why not just buy a commando hub assembly with the cush drive
And lace your existing rim onto it
You can re use the spokes
Do the job yourself
Click to expand...
OP has a cast rear wheel he hangs onto. However, if the lack of a cushed drive is a real concern, replacing the wheel by a semi-cushed Norton hub (1971-74) or a proper cushioned hub (Pender) with the necessary ancillaries should be a breeze.

- Knut
 
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baz said:
Whilst I agree this should be a possible engineering alternative the t140 clutch is vastly inferior compared to a commando clutch
Click to expand...
You are probably right. The Laycock clutch design is hard to beat. However, there is a 7 plate clutch plate conversion for the T140 clutch which along with stronger springs is said to transform the clutch.
Presently unavailable according to L.P. Williams.

- Knut
 

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