i have a 2001 speedfight 2 50cc. it has a leovince race exhaust, its de-restricted and has up-rater rollers. recently it has started backfiring and popping quite badly when i start it up and when i let off the throttle. i was told it needed a new exhaust gasket so i changed that and it has made no difference. still goes well but fuel consumption is terrible. about 8-15 miles per half a tank? can anyone help?

sam, July 2012

I'd be inclined to try a different HT coil, your one sounds banjoed. Pick up one from a breakers, you can always bring it back for a refund if it's not the problem.

Steo, July 2012

start the engine and hold a rag over the end of the exhaust, if there's a hole or leak in the exhaust you will hear a hissing noise as the pressure builds up, you should be able to find it easy from that and have it welded up or double check that any seal is seated and bolts are tight.

Pitkin, July 2012