I am in the middle of restoring a 64 Dot with 37a square barrel motor for classic pre65 trials competion here in Australia,but it is hard to get any info over here.

I need to known the best set up for trials gearing,primary rato ,secondary ratio front rear sprockets etc. ,gearbox ratios etc,,,it looks like this motor has had the gearing changed in past maybe to used as a scrambler so i need to known the the best set up for trials and where to get sprockets gears etc.

What sort of 1st gear ratio should be aiming at.

Thanks in Advance Peter

You may have agricultural three wheeel tractors known as a Gnat in Australia, I have seen them here in NZ. I can tell you that the NZ Gnat version has a Villiers engine fitted with Wide Ratio gear cluster - suitable for your DOT project, which should fit directly into your engine if I recall. It could be worth advertising in Australia and New Zealand to see if you can find a Gnat that just might have a good Wide Ratio gear cluster suitable as a Trials gearbox. Brian H