Thanks for all the replies, it's good to get different ideas. I was thinking exactly the same as the diagram above when I started but then you realise that the output flange on the Reliant box will need an outrigger bearing as it is not designed to take any sideways load and the driveshaft also needs supported. Also, the distance between the cog on the Reliant box and the one on the driveshaft is quite small meaning you would be restricted in your cog size which affects your choice of gearing and means the chain will not drive on as many teeth as you might like. Or, you could mount the driveshaft on the other side and flip the rear wheel over and mesh the two cogs but that would be even harder to engineer. Which ever way you really need it to run in oil so that means an eclosed box. Then you wish you'd just bought a CG125
. As you can tell, I've thrown a lot of ideas about and this just seemed the best way to go. Hopefully, time will tell.
