Category Archives: Motorbikes

CG250 engine project begins in earnest

I bought a 167FMM CG250 (233cc) Chinese copy engine. I’d like to use it in my recently completed silver CG125 but as the old CG125 is 6v with points ignition and the CG250 is 12v with electronic ignition I don’t much fancy changing the wiring harness and all the light bulbs. So I have been investigating swapping the crankshaft and cylinder, piston etc to some spare CG125 crankcases I have. The first issue is the crankcase cylinder opening size isn’t big enough to accept the larger cylinder liner, so today I set about boring the crankcases to accept the bigger liner.

The CG125 is street legal

I had the day off work today. Got my CeeGee through compliance and then decided to further investigate swapping the Chinese CG250 internals into Honda CG125 cases. Got quite a long way in when I discovered the main bearings are different sizes. Gave up and put it back together. I’m so chuffed I bought a small Makita impact wrench. Made the process so much faster and easier, although I did have to get my air one out a couple of times on really tight things. I didn’t know but square number plates are now a thing πŸ‘

Engine painted

The engine came up pretty well in the photos, not quite as nice in real life. I used a wire brush on electric drill along with a small brass wire brush, then degrease, pressure wash then 400 grit wet and dry. Pressure wash, dry with compressed air, heat gun and paint. Lockdown achievement accomplished πŸ™‚

Beach life.