Primary Belt Drive Identification.

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Aug 7, 2004
I recently decided to switch to primary belt drive for my Mk3 Commando, and bought this neat looking primary belt drive / clutch assembly from my local Norton mechanic / parts pusher. However he doesn’t want to reveal the manufacturer of this product to me, making me suspect that I probably paid way to much for it.

I paid what would convert to about GBP £600 or USD $1100 for the kit. It looks absolutely beautiful and well crafted and I’m really looking forward to a lot les noise and a proper clutch operation with this.

I would like to know just how much this kit really costs, and also it would be nice to see some kind of documentation / info / instructions, as I didn’t receive any paper work at all at the purchase.

Do any of you guys recognize this belt drive kit, and does anybody know the manufacturer or dealer?? The only identification I have been able to locate is a circle stamp with the letters BNR in it.


See the photo:

Wow. Look at that clutch setup, will ya? I'm very interested in the manufacturer and if it works as well as it looks like it should.
Hi Niels,

Indeed, you have bought yourself a fine looking primary belt drive kit!!!

I just love looking at finely crafted motorcycle components, or any finely crafted mechanical component for that matter.

Sorry, I don’t recognize the manufacturer. I feel you are on right trail to get an instruction manual. My experience with belt drives is that proper tension is critical to the life of the belt. This is the kind of information that should be included in the instruction manual.

Also, the MK III Commando does not have a way to move the transmission fore and aft; so I’m not sure how you will make belt tension adjustments. Is this kit designed for a MK III?

Lastly, belts abhor oil, so make sure your engine and transmission seals are leak-tight before installing the belt.
I don't recognize that kit either, but I recently purchased a kit specific to the MK III that allows the retention of the electric start. I got the kit from RGM and the cost was 240 GBP. The kit I got has a hardened steel sleeve in the drive sprocket that allows the sprag to work. Also since the sprag needs lubrication the belt appears to be a steel reinforced nylon which should be fairly resistant to the ATF I plan on running in the primary. The kit also has an adjustable transmission bolt that in theory will allow me to adjust tension on the belt (see Jasons last comment). Since I haven't installed the kit yet I don't know how it will work but it appears to be well thought out. Time will tell. The only concern I have is the bolt to adjust tension since I can't imagine how it will work. BTW I think Norvil also sells a Kit for the MK III that keeps the starter as well as one that leaves the starter off. The one that leaves the starter assembly off is quite a bit cheaper and probably avoids the worry of oil eating the belt.

Stuck in and wearing thin
Looked at the picture again. Appears the kit you have uses a Triumph or ? clutch basket assembly. The kit I got from RGM keeps the Norton clutch, for better or worse. Time will tell.

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