I bought a 1983 CB125 RSD as sold as seen, with an MOT..I taxed the bike and had a re-MOT all was ok. until I took the cover off and realised it had an alternative engine fitted, which turned out to be a Honda 1976 J engine which had been rewired to suit. .Since then I bought a second hand engine of the same vintage as the original Using the same carburettor. It starts up with ease on the kick start and ticks over no problems until it reaches about 4000 RPM after will not rev much higher' I have fitted new points and checked timing,fitted spark plug and lead,new coil and condenser. I have also tried an alternative Carburettor, but still no joy. Please can anyone Help with my problem
