Decided that the little 250 cruiser needed a bit more to cruise with the bigger boys, so -

Stage One - take off the head and open up the very restrictive exhaust ports, clean up the inlets, and remove the steps from the inlet manifold. This allows far better breathing, so my old complaint about carburation falls away.

Then, stage two - bore it out to 56mm and fit Honda CG125 pistons. You have to mill a small squish band on the head of the piston to accommodate the bigger bore. This pushes capacity to 265 from 233cc.

I had all this carried out by the local agents, TT Motorcycles. I previously changed the standard 32-tooth rear sprocket for a 29-tooth, giving a calculated true speed of 140kmh at 8500rpm and 120kmh at 6500. The bike now pulls this gearing with ease and has much more torque.

I intend to take the beast on a 1200km trip in the next two weeks, travelling with a bunch of kindred spirits on nothing less than 750s, so will report back on reliability, fuel consumption, etc on my return.