I guess this question has been asked a thousand times but I couldn't find the answer.....

I bought a MC21 SP last Autumn and spent winter sorting it cosmetically, now I'm trying to sort the engine. The bike pulls well up to about 8000rpm but then coughs and splutters. I did the orange/blue wire mod but the gear position work hasn't been done.

Sitting here at the PC I don't know whether to go for carbs, ignition, power valves or whatever so any pointers would be welcome.


On the last two stroke I owned (RD400) it was a case of clean the plugs and off you go but this is a little more complex!

Thanks in advance.

Chris.