FYI, as of 2016, the BNR clutch features a sealed roller bearing according to entries in the Britbike forum.
- Knut
Last edited:
Norton vs Bob Newby clutch (2016)
- Thread starter Matchless
- Start date
- Status
- Knut
Fast Eddie
VIP MEMBER
- Joined
- Oct 4, 2013
- Messages
- 21,594
I don’t think that’s correct. I think it is a large diameter bearing, but still dismantle-able and grease packed.
I will ask the man himself. I wanted to pose another question anyway.
Fast Eddie
VIP MEMBER
- Joined
- Oct 4, 2013
- Messages
- 21,594
Please let us know.
- Joined
- Jun 30, 2012
- Messages
- 14,006
The early Norton clutch with single row chain and coil springs is probably as good as any other for racing. A Barnett clutch is made from aluminium and is probably even lighter. For my engine sprocket, I use a splined carrier and Jawa speedway sprockets. Makes it much easier to change the gearing to suit the circuit. The set-up is reliable enough for racing, but for road use it would need a supply of lubricant for the chain. The original Commando set-up is heavy.
Bob replied but evaded replying on the bearing issue. Current advertisement says that "The hard-anodized aluminum clutch basket features enclosed bearings, no hassles with installing loose ball bearings, ...." . I asked for clarification on this statement. No reply so far.
- Knut
Fast Eddie
VIP MEMBER
- Joined
- Oct 4, 2013
- Messages
- 21,594
Yes, I think ‘enclosed’ is perhaps the correct term. As supplied, the unit is assembled and the bearing is ‘enclosed’.
But it is dismantle-able and not a properly sealed bearing.
Fast Eddie
VIP MEMBER
- Joined
- Oct 4, 2013
- Messages
- 21,594
I knew it had been discussed somewhere before. This is a Triumph application however, see pics in post #58…
www.accessnorton.com
Fitting a Bob Newby belt drive
When I was at P&M a couple of years ago I was chatting with Dave about a TR7 motor he had built for a bloke. He used a Matchless type breather in the end of the crank. The drive side shaft is drilled to 1/4" dia & the valve fitted to the end & used to hold the alternator rotor on as per AMC...
www.accessnorton.com
Onder
VIP MEMBER
- Joined
- May 11, 2010
- Messages
- 4,264
Yes the BNR clutch I have is NOT a sealed bearing. It needs to be greased but how often I don't know I do it once a year
but then that is low miles. The standard Norton or NEB approach would be better why Bob went with the tiny balls I cannot say.
It would surely win if weight was the issue.
but then that is low miles. The standard Norton or NEB approach would be better why Bob went with the tiny balls I cannot say.
It would surely win if weight was the issue.
I suspect the bearing is that way because or the R in BNR .
Race bikes receive a lot more attention per mile than our roadbikes generally get.
So it's a super lightweight racing clutch that will handle racing output but needs racebike style maintenance.
Also, the big diameter of the Newby Race sure reduces clutch wobble. This is probably more important to a racer as well.
For the road we can put up with some clutch wobble as long as we don't have to disassemble the damn clutch just for maintenance every year.
I was looking forward to the no maintenance aspect of my RGM belt drive, however on disassembly for frame painting at about 25 miles, most of the sealed in grease has flung out of the bearing!
Glen
Race bikes receive a lot more attention per mile than our roadbikes generally get.
So it's a super lightweight racing clutch that will handle racing output but needs racebike style maintenance.
Also, the big diameter of the Newby Race sure reduces clutch wobble. This is probably more important to a racer as well.
For the road we can put up with some clutch wobble as long as we don't have to disassemble the damn clutch just for maintenance every year.
I was looking forward to the no maintenance aspect of my RGM belt drive, however on disassembly for frame painting at about 25 miles, most of the sealed in grease has flung out of the bearing!
Glen
Fast Eddie
VIP MEMBER
- Joined
- Oct 4, 2013
- Messages
- 21,594
I wouldn‘t dismiss Bobs efforts just yet. I’d say the reason he went for the large diameter bearing is it’s greater load capacity and next to no wobble.
I think it’s also worth pointing out that the bearing only comes into play when the clutch is in. So, as with any sympathetic use of any old Brit bike, so long as you don’t make a habit of sitting at the lights with the clutch in, the bearing doesn’t get an awful lot of use.
There are lots of Bobs kits on the road and track, I’m not aware of horror stories of failed bearings…
I think it’s also worth pointing out that the bearing only comes into play when the clutch is in. So, as with any sympathetic use of any old Brit bike, so long as you don’t make a habit of sitting at the lights with the clutch in, the bearing doesn’t get an awful lot of use.
There are lots of Bobs kits on the road and track, I’m not aware of horror stories of failed bearings…
Last edited:
I hope I didn't sound dismissive of the BNR clutch- I have two and they are wonderful. I was just attempting to explain the bearing choice.
One other point- when I disassembled the Vincent 1360 for crank rebalance at 1500 miles, the Newby clutch was removed and inspected.
All of the grease that Bob packed in there was still inside. I didn't repack it as there was no need at all.
It faired much better than my sealed clutch bearing has!
One day I will remove the 650ss clutch as it has 7 or 8 thousand miles on the BNR drive now.
I do kick bikes out of gear at stoplights, even the modern bikes.
Glen
One other point- when I disassembled the Vincent 1360 for crank rebalance at 1500 miles, the Newby clutch was removed and inspected.
All of the grease that Bob packed in there was still inside. I didn't repack it as there was no need at all.
It faired much better than my sealed clutch bearing has!
One day I will remove the 650ss clutch as it has 7 or 8 thousand miles on the BNR drive now.
I do kick bikes out of gear at stoplights, even the modern bikes.
Glen
Last edited:
- Status
