It is not the overall gearing which was too high - only first gear. I have several pairs of first gears from various earlier boxes. I could have fitted a much lower first gear and tolerated a much bigger gap between first and second. However I have doubts about the strength of those older gears. The problem is only in the first few yards of any race, once the bike is up to about 30 MPH there is no problem. It is just that first few yards which are too slow. I have progressively reduced the size of my rear sprocket a tooth at a time and each time it became better - once the bike is mobile.
It is a problem which is not easy to identify. You can accelerate down a straight believing the bike is going as fast as it can. However when you raise the overall gearing by one tooth, the bike becomes faster - it is not what you would expect. My feeling is that the heavy crank always tends to spin up at the same rate almost irrespective of the gearing. I try to always keep it on the boil.
The reason I bought the 6 speed TTI box is that the gear spread is much wider, so first is now lower when I use the same high overall gearing. Since I've fitted the TTI box, I have gone even higher with the overall gearing - 6 close gears get you there even faster. The close box with the heavy crank and methanol fuel, is magic. The old 4 speed Norton close box was excellent everywhere except off the start. You cannot live with the situation where you have to choose between a good fast start and running out of steam towards the ends of the straights. You need fast everywhere.
