Vic, I do not think there is any doubt that you are a brilliant engineer, and your analysis and solutions to the perceived design flaws of the Vincent motorcycle are always interesting and informative.Even so, they will have same old bevel drive to the camplate I´d think. Same with the Surtees 5-speed gears. I don´t have war with the G 49 alu bit - when it does not double with the gear change stops for not over- or underselecting gear change. It is just not great wanting to stop the mass of the actuating arm in the action at the very close grub screws in the G 49 near the gear lever shaft. Too much force there and no reliable positioning at the G 59AS change speed pawl place at that distance from the lever stops.
When deciding on lever stops at the G 49 and grub screws you want that G 49 to be put absolutely solid at its place. So then another flaw with the two fixing screws , one of them the excentric G 57 stop plate adjuster. My memory is clouded about some poor fits of the old excentric screw on the G 49, did not look solid or reliable, rather mangled bits. So , well, another devation, had some plates for the two screws made, plus a separate excentric roller, no hex head on it. I don´t do fine adjustments here, only centralizing the lever roughly for middle position. Then do the non-excentric screw up, throw in the excentric roller plus a split washer for some preload on the roller so it does not move when the lot is finally fixed for good.
Vic
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My point being that Ben Kingham (and Tim) are also doing something quite remarkable on the track with a Vincent Black Shadow, Ben competes with the very best that Classic racing has to offer, and often wins.
I don't know how many gears Ben is running, 4 or 5, certainly not as many as a Suzuki RK67 that ran 14 gears to keep it in a very narrow power band, but whatever Ben is running, I would imagine that even with the abundance of torque that Ben has at his disposal, he is still having to make plenty of gear changes to compete with the opposition, with no margin for false neutrals or missed gears, so despite your reservations with regards to the efficacy of his modifications, they appear to function reliably, and exceedingly well.