Racing a chopped twin using belt drive

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Denis Curtis

Forum User
Non-VOC Member
Am putting together a racing twin using a chopped motor (purchased that way) and mated to a Norton Commando gearbox. Am using Norvil racing belt drive kit and fitting all inside the big Commando aluminum chain case with large vents!. The engine started life as a 998 and now is up to 1350cc thanks to Terry P.

My question is about gearing, (Norvil have a considerable amount of options regarding gear ratios, re engine sprocket and clutch sprocket) does anyone have experience with a belt drive of this type and set up(1350cc)?, if so please contact me either on this forum or directly.

Best regards to all,
Denis Curtis
CMR Racing Products Inc.
Formerly Curtis Racing Frames
Belleville Ontario Canada
curtisracing@sympatico.ca
www.cmrracingproducts.com
613-967-8112
 
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timetraveller

Well Known and Active Forum User
VOC Member
Hi Dennis, Roy Robertson uses a similar set up with a big chopped Vincent engine and Norton gearbox. He uses a Bob Newby set up designed for that combination. It consists of a 44 toothed engine pulley, a 68 toothed clutch pulley and a 40 mm wide belt. He has a 21 tooth gearbox sprocket and then the final sprocket depends upon the circuit. Roy would be happy to answer any phone questions and his number is
*********
 
Last edited by a moderator:
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timetraveller

Well Known and Active Forum User
VOC Member
Nulli. I would not have included Roy's phone number without his permission. In the last MPH I included both my phone number and email address and the current paranoia about our bikes and their stupid prices should not stop us helping each other. If someone is really stupid enough to try and steal from me then all I can say is that whatever happens to them is their own stupid fault. Roy is happy to help. Give him a chance to.
 
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timetraveller

Well Known and Active Forum User
VOC Member
OK. Roy just phoned me and as he is not a computer user and hence not a viewer of this Forum he had not realised that when I asked him if was OK to give his phone number that the number would be public. A lesson to those of us who use this Forum and interact with those who do not. It is too easy to assume that people know what you are talking about. Lesson learnt and I will now go stand in the corner! Oh dear.
 
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Denis Curtis

Forum User
Non-VOC Member
Thank you so very much for such instantaneous responses. I will contact Roy shortly about his experiences. I have read about his exploits with much relish in the pages of MPH. Thanks particularly to Timetraveller and the our Forum moderator. Anyone thinking of coming to the North American Rally here in Ontario on June 10, 11, 12, just outside Niagara Falls? You'll be sorry if you miss it. Canada is Fantastic at that time of year.
Regards,
Denis
 
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roapro

New Forum User
Non-VOC Member
Hi Denis, I have the second chopped motor special that you did years ago, Leno still has the first, and was wondering about a similar belt drive configuration. I was looking at a unit manufactured by RGM Motors in England however it is only a 32mm belt drive, and I am unsure of the gearing. Does anyone have any ideas of incorporating an electric start system on the Norton Commando primary arrangement? I am in need of a knee replacement and have purchased a Groset unit for my Prince but I would really like something for this Special.

Cheers, Scott Best
 
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