Power assisted motorcycle clutch cable. Ideas?

[Greeves246]

Suffolk Motor cycles are showing as having one for sale CB 400 hawk Auto 3000 miles 1978 £6000 ish.

Many years ago when repping I had a customer, Vernon Leigh who had a bike shop in Stockport. Vernon had a 400A as he had an artificial leg and one day was knocked off it by a woman driver. As his bike slid away it pulled off his artificial leg and Vernon was sat in the road with a little blood seeping through his flat trouser leg screaming “ get me my leg, get me my leg”. The woman got out of the car and assumed she had ripped his leg off, fainted banging her head and had to be taken away in the ambulance. Vernon attached his leg and rode home.

 

[CompoSimmonite]

As already said NABD are the people who can help.
What about the dual right side levers - one for clutch and other front front brake ?
https://www.nabd.org.uk/adaptationkits/

 

[atomant48]

Weaker springs in the clutch sounds like a good avenue - and take it easier on the gas away from the lights !

Other idea (since it’s a mig welding forum) might be a wire feed roller in the cable run … suitably beefed up motor and a micro switch to activate it as you pull the lever. Not sure on the retraction …

 

[jsf55]

From years of riding a push bike .... can you not swap levers over, front brake on the left side and clutch on the right for the stronger arm, it will take a little time to get used too but at least it'll beeasier too upgrade a hydraulic brake ?

 

[Hood]

From years of riding a push bike .... can you not swap levers over, front brake on the left side and clutch on the right for the stronger arm, it will take a little time to get used too but at least it'll beeasier too upgrade a hydraulic brake ?

As I said earlier the majority of braking on a motorbike is with the front brake, probably as much as 80-90% I would say. Swapping the front brake to the weak hand will not be the best idea in my opinion.

 

[Misterg]

Any arrangement of pulleys or levers is only going to trade effort off against distance - it needs some external power source.

I'll try and describe what I'm thinking of:

A linear actuator attached directly to the clutch operating lever (on the engine). The operating lever can be extended if necessary to get enough force to disengage the clutch.

e.g. something like this:

Amazon.co.uk

750N / 100mm max travel / 10mm/s

Also on the operating lever, and moving with it, would be a plate holding a couple of microswitches.

The microswitches would be wired (through a couple of relays if necessary) to run the actuator when pressed - one forwards, one backwards.

The cable from the handlebar clutch lever would be attached to a free moving 'cam' fitted between the microswitches so as to actuate one or the other when pulled or released, but have a neutral position in between.

In operation, the handlebar lever is pulled, pressing one of the microswitches, causing the actuator to move the clutch operating lever. it will keep moving until it has moved far enough that the microswitch releases and stops the actuator. If the clutch lever is released, the cam will contact the other microswitch, causing the actuator to move the other way. The actual position of the operating lever will thus reflect the actual position of the handlebar lever.

No electronics needed. (Same principle could be used with pneumatics / vacuum or oil pressure if there was a suitable source available.)

Potential downsides:

Engagement / disengagement might be quite slow.
Gradual movements of the clutch lever will probably cause stop-start operation of the actuator.

 

[minimutly]

Weaker springs in the clutch sounds like a good avenue - and take it easier on the gas away from the lights !

Other idea (since it’s a mig welding forum) might be a wire feed roller in the cable run … suitably beefed up motor and a micro switch to activate it as you pull the lever. Not sure on the retraction …

That's a non starter, it would slip on acceleration in 3rd..

 

[jmp49]

I toyed with the idea of removing a couple of springs from the clutch, or a mate even suggested getting some weaker ones made. He has a contact that can do that, from back in his racing days.

I toyed with opening up the clutch to see if I could do any modifications to it, or it’s lift mechanism, but looking online everything is so compact and complex it would take some very skilled engineering to improve on the design.

However, my weakness is caused by a degenerative disease, MND, so it will only ever get worse. I used to go to the gym twice a week but found it got harder and harder, and Ive been told it’s not advisable in my situation.

There’s probably no perfect solution to my problem, just ways to keep me on two wheels as long as is practicable, and safe.

The lockup setup uses far weaker springs, so the clutch would slip under power. Except there are some levers that have weights on the end that spin on the clutch front face, and you put weights on the end of the levers and they are thrown outwards via centrapetal force with rpm so it helps the clutch lock up solid at higher rpm, and compensate for the weaker springs. On a stock bike clutch those springs are sized to stop slippage at high rpm in higher gears where the load is the highest, so you can go quite a bit lighter and still have it work as a normal not slipping clutch at pulloff speeds.
The idea on the original design is you want the clutch to slip controllably on a hard launch at lower(ish, its still going to be 3-4k) rpm as its a dragbike/car thing, then dial in when the clutch locks solid by altering the weight (aka a nut and bolt with some washers on). The outer cover needs space to clear the levers, the 1100 has a spacer to keep it discreet, but the turbo setup has a modified cover. There's a lot of moving things flying round, hence keeping a eye on its health is a good thing.

Here's the one off my dragbike I made, but I run one on the two road bikes mentioned too, and they're much of a muchness, levers that push the on the original outer of the clutch pack together and assist the springs. The levers are tool steel & I made the alloy basket/outer plate bespoke on my cnc. Its all monsterous because the bike was being built for 500+ hp territory on a 1976 z1-900 base and ran a funny car bronze plate frictions but the principles of the mechanism are the same.
I got a commercial one off the shelf for one motor, and they didnt even add wear inserts for the end of the hammers and it was starting to wear through the original clutch outer as a result, but it wasnt complex to make four holes and put some hardened steel inserts in the oem clutch outer plate.



Contact NABD for sure, but also if there's anyone drag racing a model that uses the same clutch face, it might be adaptable to yours. There are companies making the spacers and clutch outers with lockup mechanisms for racing use, the 1100 is running a MRE spacer which is just a lump of alloy cut out to clear the clutch and space the original cover out further to hide it. Its very discreet indeed...

Also, there are the odd auto petrol engined bikes out there. Less rare more recently, it used to be cb400's and c90's and the like with automatic transmissions, but now theres a raft of dct equipped bikes, the problem is not very much midrange stuff. Just big or little. The almost middleweight NC750X is out there, but I imagine they are pricey...

 

[reb78]

Suspect this is a silly suggestion but you couldn't put a second foot pedal in somehow on the right side could you? It'd take a bit of getting used to even if you could!

(I'm not a biker so could be a real stupid idea!)

 

[Robotstar5]

Land Rover introduced a spring assisted clutch pedal in the 90's to reduce the effort needed to depress the pedal, wondering if some sort of spring could be attached to the bike clutch lever to do most of the work?.

 

[reb78]

Land Rover introduced a spring assisted clutch pedal in the 90's to reduce the effort needed to depress the pedal, wondering if some sort of spring could be attached to the bike clutch lever to do most of the work?.

Theres also the red booster servo assist made to fit land rovers but i am assuming this is all cable operated on the bike. Its probably too complicated but could a hydraulic system be adapted and be easier to use for @Morrisman

 

[Morrisman]

Land Rover introduced a spring assisted clutch pedal in the 90's to reduce the effort needed to depress the pedal, wondering if some sort of spring could be attached to the bike clutch lever to do most of the work?.

I really can’t imagine how something like that works, as it’ll be simply fighting against the springs in the clutch, any lift mechanism would be rubbing or revolving continuously.
If anybody knows the secret I’d be interested.

 

[Morrisman]

The lockup setup uses far weaker springs, so the clutch would slip under power. Except there are some levers that have weights on the end that spin on the clutch front face, and you put weights on the end of the levers and they are thrown outwards via centrapetal force with rpm so it helps the clutch lock up solid at higher rpm, and compensate for the weaker springs. On a stock bike clutch those springs are sized to stop slippage at high rpm in higher gears where the load is the highest, so you can go quite a bit lighter and still have it work as a normal not slipping clutch at pulloff speeds.
The idea on the original design is you want the clutch to slip controllably on a hard launch at lower(ish, its still going to be 3-4k) rpm as its a dragbike/car thing, then dial in when the clutch locks solid by altering the weight (aka a nut and bolt with some washers on). The outer cover needs space to clear the levers, the 1100 has a spacer to keep it discreet, but the turbo setup has a modified cover. There's a lot of moving things flying round, hence keeping a eye on its health is a good thing.

Here's the one off my dragbike I made, but I run one on the two road bikes mentioned too, and they're much of a muchness, levers that push the on the original outer of the clutch pack together and assist the springs. The levers are tool steel & I made the alloy basket/outer plate bespoke on my cnc. Its all monsterous because the bike was being built for 500+ hp territory on a 1976 z1-900 base and ran a funny car bronze plate frictions but the principles of the mechanism are the same.
I got a commercial one off the shelf for one motor, and they didnt even add wear inserts for the end of the hammers and it was starting to wear through the original clutch outer as a result, but it wasnt complex to make four holes and put some hardened steel inserts in the oem clutch outer plate.
View attachment 498549View attachment 498550View attachment 498551
View attachment 498552

Contact NABD for sure, but also if there's anyone drag racing a model that uses the same clutch face, it might be adaptable to yours. There are companies making the spacers and clutch outers with lockup mechanisms for racing use, the 1100 is running a MRE spacer which is just a lump of alloy cut out to clear the clutch and space the original cover out further to hide it. Its very discreet indeed...

Also, there are the odd auto petrol engined bikes out there. Less rare more recently, it used to be cb400's and c90's and the like with automatic transmissions, but now theres a raft of dct equipped bikes, the problem is not very much midrange stuff. Just big or little. The almost middleweight NC750X is out there, but I imagine they are pricey...

I started making something similar for my V8 bike project years ago, but didn’t have access to the machine tools required, so gave up on it eventually. Nowadays I’d be paying someone to do all the work. And if something broke I’d be waiting an age to get parts made.

Simply to remove the clutch cover requires draining the cooling system, removing the water pump, a bunch of other fiddly stuff too, before you can get to even see the clutch.

I can see me moving to a bike that already has a centrifugal type clutch system eventually.

 

[Morrisman]

Weaker springs in the clutch sounds like a good avenue - and take it easier on the gas away from the lights !

Other idea (since it’s a mig welding forum) might be a wire feed roller in the cable run … suitably beefed up motor and a micro switch to activate it as you pull the lever. Not sure on the retraction …

Maximum power comes in at 9500rpm, 34bhp, but I don’t think I’ve ever revved it above 7k. As mentioned, there’s a lot of spannering just to access the clutch, work I’m not sure I could actually do it myself.

 

[Beanwood]

OK - CRAZY off the wall idea with no thought behind it - how about changing the gear lever so that it operates as a clutch lever as well as a gear lever - so it pivots as you push 'in' towards the gearbox, operating a cable and the clutch engages, shift up or down as usual, and then release the pressure on the clutch.

Slightly convoluted, but it works in my head, and could be done without changing the existing clutch or lever!

 

[Greeves246]

OK - CRAZY off the wall idea with no thought behind it - how about changing the gear lever so that it operates as a clutch lever as well as a gear lever - so it pivots as you push 'in' towards the gearbox, operating a cable and the clutch engages, shift up or down as usual, and then release the pressure on the clutch.

Slightly convoluted, but it works in my head, and could be done without changing the existing clutch or lever!

Triumph did it , called slick shift late 50s early 60s

 

[Beanwood]

Triumph did it , called slick shift late 50s early 60s

Damn - no such thing as an original idea any more.....
So it's possible then...

 

[reb78]

Damn - no such thing as an original idea any more.....
So it's possible then...

After posted above, I did a search and there's a guy on YouTube putting one on a harley I think. I can't quite imagine how it works tbh!

 

[jmp49]

There's the clarke one light clutch conversion too, but they are for hydraulic clutches, so you would have to convert to hydraulic then have one fitted. They claim to store the spring energy as you release the clutch then deliver it as assistance when you pull it back in, making any clutch one finger operation. Theyre quite well promoted in motox circles...

One Light Clutch – CLAKE

www.clake.com.au

For the hydraulic conversion, maybe you could get one of the slave/cable converters fitted just to be able to use the clarke.

I'd be tempted to ping clarke themselves see if they might be thinking about a cable version...

 

[jmp49]

Magura do a cable to hydraulic conversion too, compared to the chinese ones its a stinger of a price, but c'est la vie.
https://www.venhill.co.uk/hymec-clutch-conversion-2100001.html
If you are going for the clarke, maybe you can buy just the slave part from magura.
You wouldnt have to open the clutch casing up to do this type of hydraulic conversion as it all sits outside.