G'day All,
Thankyou for your comments, and sorry for the delay in the reply to your questions/suggestions, but here I go.
kamilb1998 - 24v in definetly on the cards, I'm looking into some LiIon batteries right now. The Winston Battery WB-LP12V40AH appears to be an exact fit, and from what I have read from other owners experience, the standard motor copes well running on 24v with supplemental cooling.
PLOD11 - probably the hardest part of making it was finding suppliers for the bearings and chains. I had an idea of how it was going to look and operate, but I used a 'design as you go' principle. The hardest physical part would have been boring the plates to a press fit for the bearings. On the motor/pulley line there are 4 bearings retaining two seperate shafts, one rotating twice as fast as the other, and all needing to be in the same axial line.
C5 ENTHUSIAST + RESTORER - Its max recorded gps speed has been 23Kph, on a slight downward slope, with an average of 18Kph over a 4Km run. The gearbox ratio is 4:1 which I am told is the same as the original (thanks Marra). And also to Jonny on this one, belts, even though I did not seriously consider them, are too wide, as the you will always need a two stage reduction to bring the drive back in line with the input shaft in order to maintain an adjustable final (or original) drive belt which leads to the 68 tooth pulley. Gears were seriously considered, but the cost would have skyrocketed. I'm still looking for a dividing head for the lathe tho...
And finally BooBoo - thanks for the offer, but I'm happy with this right now, and feeling much more comfortable when someone pushes the 'go' button from a standing start.
Jason