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Belt primary drive information

Submitted by terry_williams on Tue, 19/05/2020
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Heavy Twins

My 1962 Dommy 88 has a belt drive fitted by a previous owner.  I have no information about it and there areNever had one of these before.no markings visible.  Can anybody tell me who made it and how I remove and replace the clutch.  I need to get the engine out owing to big end failure.

Submitted by adam_davis on Wed, 20/05/2020

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Hi Terry, mine looks the same as yours, I got it from Mike Pemberton (Pushrod Performance) who sourced them from Mick Hemmings. You need the diaphragm compressor to take it apart which is an easily sourced tool as the clutch is the same as the Commando type. Commiserations on the big end, hope it wasn't too traumatic.

Thanks for that.  Just the L/H big end gone but it's got 4mm up and down play at TDC so I think it has to be done.  The rest of the engine is vgc so I suspect that someone didn't clear the sludge traps.  

Submitted by jan_nelder on Wed, 20/05/2020

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as above, cannot be safely done without the standard Commando tool, from usual parts suppliers. Do you have workshop manual?

    for useful photos etc on parts of Nortons, , see oldbritts website and Mick Hemmings DVDs.

Submitted by terry_williams on Wed, 20/05/2020

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I've got several workshop manuals for Dominators but nothing on belt drives.  I am a bit paranoid about springs following an incident with a Triumph sprung hub 58 years ago.  I'll have a look online.

Cheers,

Terry

Submitted by john_oldridge on Thu, 21/05/2020

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Hi Terry

I agree with Adam, I also got mine from Mick H.  I have the removal tool for the large circlip if you are near N Yorkshire  (It could  class as a necessary journey!)  and you are welcome to borrow it. 

Regards John O

Submitted by david_hammond on Tue, 26/05/2020

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I'm considering fitting a belt drive to my 1962 88SS, possibly a Bob Newby.

Some time ago I read that this was a no no because of the lack of a "cush" resulting in possible damage to the gearbox.

Has anyone got some up to date advice on this please?

david.

i,ve used newby belt drive,s on my 650ss and es2 for years with no problem,s.

i also have a commando with a rgm belt drive using the standard commando set up and find the power take up is better with a spring clutch...

Submitted by philip_hannam on Tue, 26/05/2020

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David......if you look through the Technical section of this site and the back issues of Roadholder,  you will find heaps of good advice on the pros and cons of fitting a belt drive conversion. Both have indexes which help with any searches.

Submitted by stan_thomas on Tue, 26/05/2020

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If you don't have the official tool, you can make something with a 1/2" UNF bolt thru a large heavy steel washer (or length of bar) pressing on a metal ring. You want to apply pressue near the periphery of that ring of holes in the spring by winding in a nut placed on the bolt. There's a drawing the the Haynes Commando manual of a DIY tool. When the tools in place, give it a good hard pull to make sure it's secure, and maybe stand off to one side, before you release that circlip. Likewise when you put it back together.

BTW: the belt looks a bit tight to me.

Submitted by steve_marshall1 on Thu, 28/05/2020

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I bought  kit from Tony and he was very, very helpful. That looks like one of his, but I guess they all look the same. RGM got theirs from him.

You need to machine 5mm off the front sprocket to take a 25mm belt for a Dommie, instead of a 30mm Commando belt - or it will rub on the chaincase (or you could space the outer chaincase).

There are two types, ones that used Commando mainshafts with circlips, and later centres specially for Dominators.

 

Steve

 

 

 



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