recently out on my gilera dna 50 and suddenly the engine become louder and the speed decreased.i had noticed that the bike was losing some power the past week before this happened bt didnt think much of it.can anybdy help with giving me a diagnosis of what they think it is as the mechanic looking at it has had it for almost a week and hasnt even started to strip the engine to have a better look.

iain, October 2007

If by 'engine became louder' you mean the exhaust then sounds as if your baffle inside the exhaust is broken/come adrift. Without the baffle in place your backpressure has altered and this is fairly critical in 2 stroke engines - partic small ones.

Dave, October 2007