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Other way round on the last paragraph, if I read it correctly.I am always reticent to say too much on mechanical engineering matters. A back ground in astronomy does not qualify me to pontificate on mechanical matters. In addition I know from when Chris was testing one of the first JE steering heads I had made that he is not only an astute rider, he is also a brave rider, having done some of the early testing in the snow. I was hoping that this discussion would bring one of the VOC's 'proper engineers' out of the wood work but no luck so far. I am not sure, but I think that the difference between me and Chris is as follows. It concerns the relationship between torque and power. It does not concern any gearing in the gearbox itself or ratios between the gearbox output and the rear wheel.
First an equation but don't worry. It will not cause brain damage.
TORQUE = (HP x 5252) / RPM
The 5252 figure is just a constant going back to the days of horses pulling barges and so on and the definition of horse power.
Putting some values into the equation then we can say that
TOQUE = (50 x 5252) / 5,250 (arbitrary rpm) which gives 50 foot pounds of torque
Now double the revs to 10.500
This now results in the Torque value dropping to 25 foot pounds, i.e. double the revs needs half the torque for a fixed value of horse power. So the way that I was envisaging this was that if we go from a standard Vin primary reduction of about 3:2 ( I don't have the exact figure to hand) to one of about 4:1 for the original Suzuki ratio then the torque would be reduced by a ratio equal to the difference between the Original Vin ratio and the Suzuki ration.
Is there an M.I.Mech E. in the house?
I had a good discussion with Bob Newby on this subject. His original belt drive for the Vincent gave a lower geared primary vs stock Vincent. It was something like 1.8 to one vs the stock Vincent at 1.6 to one. This would increase torque on the gearbox.I was told that a belt drive will increase the load on the twin gearbox my calculations concerned just the gear ratio I had to make an adapter for a smaller than standard range of rear sprockets. I would be interested to know how much more torque per revs is transmitted by the gearbox
View attachment 33112
So you have 36 teeth on the engine vs 35 stock?The standard ratio is 1.6 i used the 36T so its 1.89
I just managed to get a standard cover on with 10mm spacers to crankcase, and nail biting milling to clutch area
That's what I had on the Egli racer when I did not have to worry about the cover also the clutch went inbord a long way and to obtain enough clearance on the pressure plate and retain enough thread on the clutch nut I screwed a face plate of 8mm alloy over the standard pressure plateThe 40 mm Newby belt drive on my bike has 71 teeth on the clutch pulley and 43 teeth on the engine pulley. This gives a ratio of 1.65 to one vs stock at 1.6. He was hoping to get to 1.6 ratio or even less, didn't have room to do it.
And then what do I find today on evilbay?I am very happy with the result but making that first cut without knowing for certain it would work on a component costing on the way to £500+ to replace was a bit of a worrying moment.