Belt Drive Nightmare Shock Horror

Previously wrote:

I am trying to fit a belt drive to my 1950 plunger ES2. The problem is that when the clutch is pulled in, it lifts the outer case off. I have even tried 'packing out' the areas where the inner chaincase mounts i.e. the hexagonal spacer and the gearbox through boltwhich gains about an eighth of an inch but thats not enough and anyway shouldn't be necessary according to the drive supplier. I have followed his directions to the letter and am left wondering if it is the right primary case for the bike. Is there a primary chaincase with a deeper clutch profile? The one I have seems to fit the inner case and the bike perfectly so could it be a variation in the type fitted for the year, rather than completely the wrong one?

IT IS DOING MY HEAD IN.

Any help very much appreciated...

Adam

Hello well the first thing you have to remember is these belt drives have a diaphragm clutch and are machined it fit the Commando so you will need to do some measuring. First thing is to take off thediaphragmclutch and fit the old ES2 clutch and taking out any washers you have fitted. Then dothe measurement of the distance between the back inner cover and the bottom of the clutch then do the same to thediaphragmclutch to see if there is any difference in the measurement and measure the thickness of the two clutches too- and see if thediaphragmclutch fits on the main shaft correctly as there may be some difference in the two and the new clutch not fitting on the shaft right ,well i hope this helps

Previously wrote:

I am trying to fit a belt drive to my 1950 plunger ES2. The problem is that when the clutch is pulled in, it lifts the outer case off. I have even tried 'packing out' the areas where the inner chaincase mounts i.e. the hexagonal spacer and the gearbox through boltwhich gains about an eighth of an inch but thats not enough and anyway shouldn't be necessary according to the drive supplier. I have followed his directions to the letter and am left wondering if it is the right primary case for the bike. Is there a primary chaincase with a deeper clutch profile? The one I have seems to fit the inner case and the bike perfectly so could it be a variation in the type fitted for the year, rather than completely the wrong one?

IT IS DOING MY HEAD IN.

Any help very much appreciated...

Adam

This may be of no help whatsoever as I know nothing about diaphram clutches.

I found the same problem on the 1959 model 50 I have just bought. I noticed that the clutch adjusting screw was further out than the book says it should be when properly adjusted and found that the wrong clutch push rod had been put in. It was 3/8" longer than the correct one and was causing the clutch to push against the outer case. NOC have provided the correct item. Correct 9 5/8" mine was 10".

Mike

Which belt kit is this Adam ? The Bob Newby kit for instance uses his own clutch, not the Commando unit.

There isn't much space at all in the chaincase of a dynamo single. In fact, based on my experience, the later AMC alloy pressure plate will not clear and neither will the slotted spring adjuster screws, even when used with a steel pressure plate.

There is a certain amount of play in the clutch assembly and if you combine this with potential wear of the thrust washer in the pre-AMC boxes, there can be quite a bit of movement at the clutch outer cover.

It might be best to space out the outer cover. It will let some cooling air in too.

I tried fitting a belt kit once offered by RGM, it used the Dommie clutch, this went onto my 19S with a dynamo and I saw that the offset of the engine pulley did not line up properly with the clutch basket, I sent panicky faxes to RGM and got little really helpful information in reply, their attitude seemed to be if the belt is a little off to one side on the clutch basket then it would work, I spent a lot of time trying to make it work to my satisfaction and ultimately took it off again, I wound up using an Atlas clutch and reverted to the reliable chain drive, this clutch absolutely does not slip with a 626cc single and I can alter the gearing to my hearts content. I've noted that RGM no longer offers that particular belt drive set-up in their catalog. I'm not saying that a belt drive is a bad idea, the convenience of not having to deal with a drippy chain case was definitely a plus, it just didn't work for me; out of curiosity I weighed all of the components of the two clutch set-ups and discovered that the belt drive kit was actually heavier than the standard clutch by over two pounds of rotating mass hanging off the end of the gearbox's main shaft.

Albert