We have had a 250tyz trials for 9 months now,it had loads of power when we first got it ,,,,,,,,its suddenly gone flat over the last 2 trials ,& seems to get very hot,,,,sounds like a old ossa with asthma,,& sometimes sounds as though its pinking ,,tryed all the normal things .carb /air filter /exhaust ect ,,,,,found nothing ,,,,,,,,do yams suffer with ign probs ,,,,

The bike has loads of compression ,starts in 3 or 4 kicks & ticks over ok,,,,,,,

Any ideas would be greatly apprtiated ,thanks rich.

Edited October 3, 201015 yr by lucky

maybe cooling system problem - fan not running? radiator air path blocked? insufficient coolant quantity?

check woodruf key in flywheel ,possable timming fault.