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Primary Belt Drive

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Primary Belt Drive

Posted by peter_holden at December 16. 2017

Mr Norvil is advertising for sale his own belt drive kit for singles, which he claims makes the machine run much smoother. Would any member who has a belt kit fitted, not just a Norvil one,  confirm such an improvement.  

Re: Primary Belt Drive

Posted by iain_brown at December 16. 2017

I have a Bob Newby belt on my wideline ES2 - a very nice piece of kit and can always find neutral with the engine running no matter whether the bike is still rolling or stopped.

I didn't notice any change in smoothness of running though, and can't imagine there being any difference if each system was set up correctly.

Re: Primary Belt Drive

Posted by albert_sheean at December 16. 2017

Previously peter_holden wrote:

Mr Norvil is advertising for sale his own belt drive kit for singles, which he claims makes the machine run much smoother. Would any member who has a belt kit fitted, not just a Norvil one,  confirm such an improvement.

 

Hi Peter,

Years ago RGM offered a Dommie clutch belt drive for my single (1958 19S) it claimed to use all the Dommie/Atlas clutch bits and would fit fairly easily. Right off, I noticed the engine pulley did not line up with the clutch drum. RGM assured me this was fine as I only needed about 16mm of belt engagement, according to them. I finished putting it on and rode the bike for a little while with the belt drive fitted. Yes, it eliminated the oil leak from the primary case. No, it wasn't necessarily any smoother, a 600cc single does shake regardless of the primary drive. I kept having all these little problems with clutch drag and the belt rubbing inside the primary case. RGM could have had the engine pulley aligned about 5mm further out to solve all this. I ended up replacing much of the clutch internals with late model Atlas items to alleviate the drag issues. Ultimately, I reverted to the chain drive and was surprised to find that the standard set up was actually lighter than the belt drive. Much of the weight being in the clutch assembly with its great alloy clutch basket.

I've noticed that RGM no longer offers that particular belt drive kit, though they do offer a belt drive kit for singles using a Commando clutch. A bit of overkill and you lose the cush hub.

Had RGM offered alternative offsets for the engine pulley, it might have worked out for me.

Cheers!

 

Re: Primary Belt Drive

Posted by boo_cock at December 16. 2017

Ive had belt drives fitted to Harleys over the years and not one of them lasted long. Not tried it on a Norton, and will not bother. On the big twin Harley they do make it smoother and lighter but, No matter how it was set up, the belt would either snap or shred itself to pieces. What they do not tell you about the ones fitted to Commandoes is that on the racers they have a short life span and are replaced each season. I found that I could not rely on them to do a 2,ooo mile plus trip to Europe without taking a spare belt. Just sort out the primary cases and stop the leaks. It's a lot cheaper.

Re: Primary Belt Drive

Posted by neil_wyatt at December 16. 2017

I agree with boo cock, seen too many stranded where a spare link and clip would have got you mobile again.

Re: Primary Belt Drive

Posted by adam_davis at December 17. 2017

I fitted a Commando type (diaphragm) clutch and belt drive to my '49 ES2. I got it via Mike Pemberton, so from Mick Hemmings originally.

It won't just fit straight on, you have to do a bit of filing/grinding of the inner/outer chain case stiffening web to get the belt to run clear, but it's straightforward other than that. It transformed the bike; no drag, no slip, no problem finding neutral, one finger pull, plus best of all, no oil leaks because it is a truly dry system i.e. the clutch release bearing is SEALED so it doesn't need an oil bath for lubrication. Down side? No cush drive. Do I notice? No.

Re: Primary Belt Drive

Posted by boo_cock at December 17. 2017

I also have a clutch on my48 ES2 that is light, does not slip or drag and is oil tight. It's the original type with an oil bath. If it's assembled properly then it works brilliantly at no extra cost.

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