yep i agree with m too, the ht caps either wear and fall of or short out to earth through the lead.very common on most 4t piaggios and gileras.have you treated it to a new plug yet?its an ngk CR9EB plug as far as i can remember.
adam bike doctor
May 2010
check your spark plug cap has a good connection, then check the ht lead for the spark plug, this happens when you have a break in it when the engine flexes
m
May 2010
Automatic Answer
We may have found other answers which could help you.
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix motorcycles.