No. The wheel base is the same just the rear of the diamond is slightly shorter in the vertical plane. It was done probably to mount the countershaft further back to allow for a longer primary chain.
As Norman Hunter told me, when he was riding there wasn't the professionalism that there is now. He used to service his JAPs after almost every meeting if there was time.
The main difference is the position of the mounting holes at the back of the diamond where it bolts to the engine plates. On a number 1 diamond they are about 20mm closer to the mounting lugs for the back end.
Good point about the tyres. A rider suggested to me that a tyre that provided more grip might be the way to go. If the tyre was designed like that then riders would have to back off the throttle more going into corners which would reduce the amount of time per heat that the engine is on 100% throttle.
OK a brief reply.Just because an engine is mounted with the cylinder vertical and only has a 2 valve head does not make it cheaper to run. 2 heavy valves are more difficult to control than smaller lightweight ones thus valve bounce occurs more easily resulting in engine damage. Bikes with engines mounted horizontally were developed as they handle better than upright ones so better handling generally results in a safer bike to ride. Lots of equipment instantly made obsolete would mean that riders wouldn't have anything to sell to enable them to invest in the new bikes. The JRM 2 valve ice racing engine costs almost the same as the 4 valve engine to buy.
Complete bike used in EL this season. GM engine, Mk2 Blixt. Jawa diamond and back end with Stuha forks. Blue Talon GP wheels. NEB clutch and countershaft. Very nice bike, ready to go. 2600 ono. PM for more details.
Well lets hope you're correct then you can feel the 'big man'. Your predictions of its demise are strange though as crowds are good but as you say you don't even go then you must be a total expert on the place.