HELP !!! Gilera DNA 50 Chewing up the drive belt

Hi all, My son has a Gilera DNA 50 but the standard speed was ridiculous so i set to work, Vespa mostly and Lambretta was my thing in the day so Variators was something new, so this is what has be done, new 70 cc head barrel and piston, larger main jet, performance variator and a 2000rpm main clutch center spring, OK so top speed is around 70mph, which is above my expectations but the issue is after a while the belt just chews up and when the side cover is removed it looks ike it has been jammed at the bottom of the clutch pulley (when thats fully open) i thought it was throwing the belt off the front and catching on the electric start cogs, 3 times it has chewed a belt now, i know this bike isnt supposed to do that speed but surely someone else must have had this problem at some point, so all help greatly appreciated, Thanks

 

Are you still using the stock belts ?

you have done the major areas of tuning, but one place that tends to get missed is the variator belt and the most basic mistake is running stock belts. your now throwing all that power through the drive system the weakest area is going to fail first and that is the belt. as an upgrade most swap to a kevlar belt to aid in longer life and stop the belt sheer your having.
both malossi and polini do upgraded kevlar belts


BTW welcome to the scooter shack Adeenuf