I'm guessing the cable is coming adrift from the lever because the lever is travelling too far, this could be caused by the mushrooming of the ends of the push rod effectively shortening it. Failing that the clutch centre could be loose on the gearbox input shaft.
As suggested above - my next move would be to remove the primary chain case cover - see if there is any end float in the cutch on the gearbox shaft, if not see how much free play there is on the clutch adjuster screw, (the one in the centre of the pressure plate).
Whatever the case you will need a replacement push rod.
Regards Mick
Thanks Mick
The push rod was bang on 10" long and I will be ordering a new one along with gaskets as soon as I have had a look behind the primary chain case cover
There are two different push rod lengths and I can't remember what they are or why they are different. I think it is something to do with the number of clutch plates. Phone Steve Surbey at AMC Classic Spares on 01462 811770 and he will tell you straight away if no one on the forum knows the answer.
Here again I know from personal experience of the PO of my bike having used a length of mild steel (unhardened) as a push rod, stripping out the clutch basket and not reassembling it correctly, hence my clutch problems.
Les
Rules are for the obedience of fools and the guidance of the wise
Cheers Les........... My push rod didn't seem to be case hard end as it cleaned up easily with a file...!
The "ball" end had a round indent but it was off centre.
Will keep you posted as to what the problem is, am actually happy to have to take the cases off so I can check what's behind.
ajsph wrote:If it is an AMC gearbox, you need to remove the kickstart lever before you can remove the outer cover, the spring will not unwind.
Regards Poul
If it's a Burman box the clutch pushrod should be 5/16", AMC one is 1/4". Your problem will be the actuating mechanism . The 3 ball bearings wear tracks in the plates and eventually it flips over. You will hear a loud click and the lever goes slack. If you have a pattern 1 1/4" handlebar lever (original is 7/8") this will give more pull, which will pull the gearbox lever too far. Sometimes you can adjust it so it doesn't quite reach that far and still gives a good clutch action.
Don't take the cover off yet, look through the filler cap hole and pull the lever. If it goes over, flick it back with a screwdriver. All the parts are available from the spares scheme.
Dave.
dave16mct wrote:If it's a Burman box the clutch pushrod should be 5/16", AMC one is 1/4". Your problem will be the actuating mechanism . The 3 ball bearings wear tracks in the plates and eventually it flips over. You will hear a loud click and the lever goes slack. If you have a pattern 1 1/4" handlebar lever (original is 7/8") this will give more pull, which will pull the gearbox lever too far. Sometimes you can adjust it so it doesn't quite reach that far and still gives a good clutch action.
Don't take the cover off yet, look through the filler cap hole and pull the lever. If it goes over, flick it back with a screwdriver. All the parts are available from the spares scheme.
Dave.
Hi Dave
You have just described the exact problem that I have........but after flicking the lever back and putting
the cable back on after a few pulls on the lever it clicks and goes slack and the cable nipple comes out.
It must be pulling the lever way too far. Also sounds like your actuating mechanism is worn. Adjust the cable so it does just enough to work (slack lever) This will do while you wait for a new mechanism! If you ordered a thrust rod for a 57 model 30 you will get a 1/4" one which won't do. It's got to be 5/16" dia. You had us fooled by not telling us it's a Burman box. Don't worry, you'll have a lovely clutch when you've finished!
Dave.
I posted this recently in another topic about replacing a clutch cable. It concerns adjusting first the clutch trust rod adjuster on the clutch. Note the ideal lever position is much like how a brake lever should be, just a bit more than 90 degrees. Less than 90 degrees the pull is shorter and may not separate plates causing drag. To far back is also not good. There more work to do with the longer pull. Would this long pull also encourage the cup and ball mechanism to over ride?
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I did mention about tie the kick starter to the gear lever, until I twigged the year of your bike which I then though should be AMC.
The correct lever angle can also be obtained by the adjuster on the clutch. As seen in the diagram too far in may not give enough to separate plates and cause drag. Laying back too much will be a bit heavy and may even encourage that clutch plate popping out the basket problem. The diagram may not look like Burman. It is intended to show the what is right and wrong on a bike in general. Note that a rear brake lever should also be at the same angle, to be correct. You will certainly feel the difference on the brake pedal and clutch lever if not correct.
