http://www.mpe07.co.uk/cb72inp.html
- Input shaft and output 1st gear to suit the standard 4sp gearbox. This pairing provides a higher 1st gear, closing the gap from 1st to 2nd.The ratio is the same as Honda provided in the race kit option 19/33-1.736:1. Can be supplied with or without kick start drillings.(Centre bush required from original gear).
From the website.
I have contacted MPE and they are available, and it is a more affordable option for those that want a more useable first gear for track.
I'm going to see how my rebuild tallies up before making a decision on a gearbox.