Are Norton Rotaries fast ?

They can be fast but what do you consider fast? A race version won a TT back in the early 1990s...just.... and that victory was probably due to the fact that it employed a belt for primary drive rather than a heavy power sapping chain. NO the belt was NOT an AT10 belt but a far more suitable Gates 8mm pitch Polychain. I was told it was a 25mm wide belt fitted to the race bike and that it stayed on for the whole season without being changed but when I measured the belt fitted to the supposed TT winning bike inthe museum long before they had that fire it was 30mm wide. I was also told by a friend 'involved' that the engine was totally knackered after the TT but he added..so were the motors of those finishing behid us.....
 
Well, in 2009 I watched Stu Garner ride one to 170 mph+ at Bonneville. He told me they had run it over 200 mph at sea level on pavement before bringing it over here to race. I'd call that fast.

Ken
 
Just a thougt....
A great many years ago at the very start of my Norton diaphragm spring clutch learning curve a NVT friend gave mew the name of the Company that manufactured the springs. I phoned and the Gent I spoke with said something like ' Bloody hell, years without anyone mentioning Norton and now two calls in a week!' Naturally I asked who the other one was from and was told it was from the rotary race shop enquiring if a stronger spring was available. Now there is only one reason for such a request...they had a clutch slip problem. This could explain why in the early days the rotary race bikes would slow down towards the end of races and not win......as I watched happen a few times on my TV. A few weeks later I phoned Mr Hele then working on the production rotaries to pick his memory banks regarding his Domirace motors and whilst doing so asked if they had a slip problem with the production bike clutches and explained about the telephoe call from the race shop to Laycock Engineering. Mr Hele, just like Mr Hopwood would, went silent whist composing his reply and then said somehing like ' We do not have a clutch slip problem with our production bikes but it should be remembered that the race motors put out more torque so they could well have a problem'. I took his answer as a YES.
The rotary diaphragm spring was Laycock 83466 Ref 70 and the drawing for all the 8 different versions of the 83466 range show that it gave the highest load of all so there was not a stronger spring in that particular size range available(6.294 inch outside diameter + 0.000 /- 0.004). And as GKN were busy closing and flogging off Laycock Engineering there would not be any either in the future!! Looking at the drawing for the pressure plate they could have increased the clamp load by increasing the diameter of the raised lip on the pressure plate (The pressure line) but in doing so it REDUCES the lift given by the lift mechanism required to free off the clutch which could well lead to freeing off problems..its know as a ramification ..you cannot sit on a start line in gear if the clutch does not free off correctly...
So IF you are seriously thinking of playing at making a rotary go faster by producing more grunt you should also be thinking of the clutch problem you could run into...... Just a thought.....
 
You must log in or register to reply here.
Back
Top