Ok guys, here is my question

Has anyone fitted a CG125 engine in an XR100 frame ?. Does it fit ?. Will the sprockets line up ?. I am not concerned about anything electrically as I am an electrical engineer and will make it run without any problem.

The reason I am asking this is as follows:

My 10 year old kid has a 2008 CRF100 and he loves it. We do some rough gnarly trails and forestry on it and often he will stall it in or drop it in an awkward place and finds it difficult to restart (he is very light and not very strong and finds it very difficult to kick when he is tired).

My plan is to buy a cheap chinese CG125 engine with electric start and fit it in place of his CRF100 motor.

If the chinese engine only lasts for a year then thats fine as he will be bigger and stronger in a years time anyway and I can put the XR100 motor back in.

Any info would be gratefully received.

Thanks a million

Fergus

Something like this is what I have in mind for the bike

These chinese engines I am familiar with. They are based on the 1979 and up Honda xl125, xl185 and xr200 engine. Regardless of the capacity of the chinese knockoff, the engine mounts are identical to the Hondas mentioned above. The xr100/crf100 engine is a different engine completely than the 125/185/200 one.  People commonly put these chinese engines in Honda xl125/185 frames when their origional engines need a rebuid and they dont know how or dont want to try to rebuild their Honda engine. Of course they can be bought very inexpesively but do turn to rubbish very quickly. You would have major fabricating to make one fit your frame.

Cheers Mark.

Fergus