The Clutch on my Comet

[Graham Smith]

Anyone who knows me will tell you that I'm not the most mechanically minded person in the world, but I'm willing to give most things a go.

On my Comet, whenever I put it in gear, it's a real 'crunch' of a gear change. Likewise, when going from 1st to 2nd, the same thing.

From 2nd to 3rd OK and 3rd to 4th OK.

I've tried adjusting it, but that doesn't seem to make any difference.

Someone has suggested that the clutch plates could be getting stuck together, but this is now getting out of my capabilities.

Does anyone have any other suggestions on what I can do to make a nice quiet/smooth gear change?

 

[Len Matthews]

Graham, it might be worth checking your handlebar lever. It depends on the distance between the pivot screw and the nipple hole how much pull you get on the cable. Can't remember the dimensions off hand but it follows that the further away the nipple hole is away from the pivot, the greater movement on the cable which may help the clutch to clear and allow crunch-free engagement.

 

[BlackLightning998]

How about selling it......

Graham,

How about selling it and buying another one, that often works!!!

Stuart

PS - Oh, and did I mention a I know a chap that would love to own one as nice as yours.........just in passing.........

 

[Graham Smith]

Russell suggested a Honda conversion available from Conways.

About £300 plus VAT.

 

[Hugo Myatt]

All my suggestions are empirical as I have no technical expertise at all. I find that any oil more than 30 weight in the chaincase causes the clutch plates to stick. Some owners use Automatic Transmission Fluid but it did not work for me. Also check the oil level in the chaincase. Some chaincases fill up with engine oil. Too high a level seems to cause sticking plates. The other problem I have had is the push rod wearing concave at the gearbox end where it bears against the ball bearing and so reducing the length of the push rod. If the Comet is unused for any length of time the plates seem to stick together. At one time I used to tie the clutch lever back to the handlebars when not in use but over time this caused weakened springs and clutch slip.

 

[Comet Rider]

Burman/Comet clutch

Hi Graham,

Just my two pennies worth.

1/ Is it just when the engine is cold, or does it happen all the time?
2/ Try Mobil 1 in the chaincase (it worked for me on both the Burman and the Conways clutch)
3/ At the risk of purists try a Honda lever assembly on the bars, as this gives slightly better lift.
4/ Finaly do you have a lot of end float in the main shaft, which can lead to loss of movement?

Neil

 

[John Appleton]

Graham, it might be worth checking your handlebar lever. It depends on the distance between the pivot screw and the nipple hole how much pull you get on the cable. Can't remember the dimensions off hand

Graham , the dimensions are :- 1 1/8 inches (best choice) and 7/8 inch

John

 

[Pete Appleton]

Looking on the bright side

Graham
My Comet started doing just this just before the clutch basket self destructed.
If the crunching is something that you have always had then the comments about increasing cable movement and trying different potions in the primary case are valid.
If this is a new manifestation then you are looking for something that is wearing out/ breaking up, in which case it is worth pulling the primary cover off and checking the clutch basket for cracks..... There is nothing on the telly tonight anyway you might as well spend the evening in the shed.

 

[Tom Gaynor]

Clutches

If one takes the chaincase cover off and observes what happens when the lever is pulled, invariably one finds that the pressure plate lifts clear, but the plates remain in a single block. ALMOST AS THOUGH THEY WERE STUCK TOGETHER. Obtaining more lift increases the pressure plate clearance. The plates however remain in a single block.
My Manx, with dry clutch, has about 1/32" lift. If I fail to strip and dry it after a wet meeting, the pressure plate will lift (it has no cover, so it isn't difficult to see) but the plates remain stuck together.
What I take this to mean is that even if the pressure plate is lifted 30 feet away from the bike, it won't make a blind bit of difference, because the problem is plate "stiction". On the Norton the cure is to part the plates one by one, dry everything off, remove any rust, and put back together again.
On my twin (with V3 clutch) my experiments indicate that Mobil1 0-something) gives minimum stiction - less than ATF, or the initial straight 40. Once the plates have freed, the clutch is everything I could wish for.
More lift isn't going to help. IMHO, the only difference using a lever with worse leverage (= better lift) is to make an already light clutch, slightly heavier.
I'm open to correction.

 

[Pete Appleton]

Prepare to be corrected

IMHO, the only difference using a lever with worse leverage (= better lift) is to make an already light clutch, slightly heavier.
I'm open to correction.

Tom
I agree with you that more lift will not solve the problem of stuck plates. BUT !! I found that with the multiplate setup on my twin, as the plates heated up during stop start work in heavy traffic they were either swelling or distorting and feeding the clutch in to such an extent that the only way to stop the bike was to stall the engine, amid much swearing, and wait for everything to cool down. Increasing the lever pivot length to 1 1/8" has cured this.
Pete