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Rob's WD16H and Big4 Forum

Dutch army, Johan Herman Fuhler, somewhere between 1945 and 1950

Rob's WD16H and Big4 Forum
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Primary case sealing band

Help please with primary chain case rubber sealing band! The Norton ones I know are the later Dommie type (which is rectangular and much too big) and a rectangular one advertised and sold for 16H which is 3/8" x 5/8". I think my friend's featherbed ES2 has a wedge-shaped band.
The 3/8" x 5/8" size is too big for my 1937 bike. I can only get it (and the footpeg) on by using a half-thickness nut. So is there another size and, if so, what is it and where can I get it from please? When I got the bike the band was totally glued in place after 25 years and I had to destroy it by cutting it out with a bent knife. I wonder if that, too, was too big?
As it happens, the thickness of the band also makes it very difficult to get the magneto end cover off and on. I suppose it is just possible that someone has switched the inner chain case but the bike is mostly unmolested original so I don't think that has happened.
Regards - David Cooper

Re: Primary case sealing band

I have an unmolested 16h. The points cover only comes off with the points in a certain position

Re: Primary case sealing band

Thanks, Jeremy. So that's normal - but do you have any idea of the size of your band? Is it relatively new (i.e. from Russels or some other Norton stockist)? And how many threads show beyond the retaining nut?
ta...
David

Re: Primary case sealing band

I'm not sure it's been apart since 43, certainly not since 64. It's a time machine. I'll check the threads

Re: Primary case sealing band

There's about three threads showing, including the domed end of the bolt that's about 4mm. However I found a large steel washer trapped loose in the casing so it may be that it should be more like 2mm. The other end is flush

Re: Primary case sealing band

Thanks, Jeremy...
No I disturbed mine to clean the clutch plates - and although it was not leaking before, it is now! Aerosol chain lube I think. Other riders get away with it (so they tell me)

Re: Primary case sealing band

Most of the problems with the primary cases are they have warped, so they need to be checked to make sure the edges are straight and line up with each other. Even when this is done and with silicone, they can still leak. Don't put them together with the silicone wet, you'll never get them apart. I put on the inner case and glue the band in place, then a smear on the outer case, let it dry before putting it together. Mine isn't too bad, I usually put some oil in every 500-1000 miles just to give it some lubrication and wet the clutch. It's not leaking at the moment but that could mean there's none in there

Re: Primary case sealing band

Mine was not leaking before this weekend. I just replaced it in a hurry. When I did it before I wiped everything scrupulously clean - no bits of grit or anything like that - and cleaned the (new) band. Then greased it and re-assembled. The chaincase on this single is much stiffer than on a Dommie - it is deeper and I think it has thicker gauge steel - so I imagine that's why it was pretty good at retaining oil. Better than the gearbox...
So now I'm fairly sure all I need to do is clean it up better. But it's still a mystery to me why it sits too far out for me to be able to wind the nut up enough to leave a couple of threads exposed - and so get the footpeg on properly. The threaded footpeg supporting tube is (I think) welded to the engine plate so unless some PO had packed the inner chain case out for some reason I cannot work it out. Unless I can find a narrow band - either 3/8" or 1/2" maximum.
Never mind. I'll just have to stay with my narrow nut.