Cush drive
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ashman
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The crush drive takes the shock out of your drive train, on the older bikes it was set up on the clutch housing and later model Commandos by rear hub, if I ever get my Dommie cafe racer built I be running a Commando clutch in it so will find out the hard way how it goes without any crush drive my 850 has the 3 paddle and 6 rubbers in the hub.
Ashley
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I would wait until the rear sprocket hub needs replacing from wear ( hooked teeth or disappearing teeth ) , then take the big plunge for entire new later model cush drive components , an easy upgrade once you realize all 3 ( front sprocket , chain , rear hub sprocket ) will all need to be changed out together to new as a matching set. It's pricey as you will likely need new hub bearings too. Loved my 70 but long gone with it's 19 T. front sprocket. Fast.
texasSlick
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The early Cdos without the cush drive developed gearbox failures. Whether this was attributed to abuse or due to shock loads from the engine power pulses is debatable, but after the rear wheel cush drive was incorporated, the GB failures abated. Thus it seems the cush drive is important.
I ran my Atlas for approx 15K miles using a Commando clutch without a cush drive, and stock Atlas rear wheel (no cush) and did not have any GB issues .... just luck or no abuse?
One factor may be, IMO, the earlier Nortons, the Atlas and Dominators, were equipped with higher quality components, which may be the factor saving my GB.
If I had an early Commando, I would consider getting a later cush drive rear wheel, for the peace of mind.
Slick
I ran my Atlas for approx 15K miles using a Commando clutch without a cush drive, and stock Atlas rear wheel (no cush) and did not have any GB issues .... just luck or no abuse?
One factor may be, IMO, the earlier Nortons, the Atlas and Dominators, were equipped with higher quality components, which may be the factor saving my GB.
If I had an early Commando, I would consider getting a later cush drive rear wheel, for the peace of mind.
Slick
Onder
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You could go the Pender route and upgrade to a modern setup. I have one and it seems good so far but honestly not many miles on it. Biggest plus to me is the ability to pull off the rear wheel in the field painlessly. That said, the later Norton cush with the current Andover Norton buffers was fine after 8K. They are a bother to install and remove though.
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The cush drive on my Seeley is in the centre of the Manx clutch. At present it is sitting in bits on a tray on my shed floor. I was pushing one new rubber into it, and it moved back and became impossible. I now need to take the whole lot off the shaft and build it on the bench. If you operate without some cushioning in the drive train, you might pit the gears and start them on their way to failure
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The weight of the clutch creates inertia, - more makes it less likely to transmit shock. It is the minor impacts which shag the gears inside the box.
What you are saying is that when you drop the clutch, you compress the cush drive because the clutch is heavy. It is not there to give you a smooth take-off. It is there to prevent damage to the gearbox.
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Not important, IMO. Even if it was, used gearbox parts are easy to find. I think the 71+ design is more for quick change convenience than for cush anyway.
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I am a big fan of cush drives. Years ago I was part of a CB750 Honda race team. We made the mistake of building a new rear wheel without a cush drive. We immediately started having primary chain failures with no other changes to the bike. Those little rubber pads remove enough shock that the rest of the drivetrain has a much easier life. Given the choice I would install cush drive every time.
I recently put a cush drive hub on my 20M3, retaining the original bolt up beauty cover. I would love to report the result but need to repair the tank that has finally deteriorated from the ethanol to the point it will not hold fuel even with a Casswell coating. Sigh.
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Back to the original questions: How important is a rear cush drive?
I think it probably depends on how you ride your bike.
For most folks, it's probably not much of an issue.
If you are doing burnouts, popping the clutch to lift the front wheel, and power shifting without a clutch, different story.
My 1968 Commando doesn't have a cush drive and I have no plans on adding one.
I think it probably depends on how you ride your bike.
For most folks, it's probably not much of an issue.
If you are doing burnouts, popping the clutch to lift the front wheel, and power shifting without a clutch, different story.
My 1968 Commando doesn't have a cush drive and I have no plans on adding one.
SteveBorland
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Hmm, I have a Maney belt drive with the light alloy clutch basket. I don't remember what you were using though?
I have a Yamaha MX rear wheel awaiting conversion into a Commando wheel, but this has no cush drive at all, so this is a subject of great interest to me.
Onder
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Will admit that another reason for the Madass rear cush mod was to make life easier for the rest of the power unit. Not having a cush has always bothered me. Sure, in most cases belts and braces, and in my case a BNR belt and TTI box too. I can indulge in this sort of expensive overkill as long as FE is on the list building his bikes. You always need someone worse off than you....
baz
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I ran a CB 750 with CMA wheels for a while it was horrible without a cush drive
And once I put an atlas back wheel in my mk2a and I didn't like that
Especially the crunch into first
My current 750 has the best setup
Light weight belt drive alloy clutch with an apprillia rear hub with a proper cush drive
Perfect clutch/gearchange/transmission
The best I have had
SteveBorland
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baz
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My back wheel is from an apprillia pegaso
It's the same wheel as a BMW funduro
The cush drive is modified for width
The hub is standard ,it's a disk type wheel but it's a 17" originally,I ran it like this for a while then I changed the rim to a 19" morrad
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If you had a MKIII assembly you could have all three. I haven't actually tried that but at first blush it seems it could work. You can do a lot with combinations of factory parts.
In the early nineties I built up a G-15CSR with a hot 750 engine mated to a Commando primary drive, as I was advised it would need the triple-row chain. I ran the original rear wheel and brake assembly for a while but when I changed tires I noticed the studs holding the wheel on were loosening in the drum. A trip to the junkyard/basement produced a complete Commando wheel and brake assembly with cush drive. So I ended up with a 19-inch rear wheel on the Matchless chassis but it handled fine. By the time I sold it I had laced an 18-inch rim onto a Commando hub and had a better tire selection. But I kept the 19-inch assembly. I have had that on my Atlas at times for a double cush drive. Seemed fine. Atlas handles a little quicker as I recall.
In the early nineties I built up a G-15CSR with a hot 750 engine mated to a Commando primary drive, as I was advised it would need the triple-row chain. I ran the original rear wheel and brake assembly for a while but when I changed tires I noticed the studs holding the wheel on were loosening in the drum. A trip to the junkyard/basement produced a complete Commando wheel and brake assembly with cush drive. So I ended up with a 19-inch rear wheel on the Matchless chassis but it handled fine. By the time I sold it I had laced an 18-inch rim onto a Commando hub and had a better tire selection. But I kept the 19-inch assembly. I have had that on my Atlas at times for a double cush drive. Seemed fine. Atlas handles a little quicker as I recall.
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