Hi I have just bought a 2005 gas gas 125, I was told petrol mix was 50:1 when bought it, so I filled it with 50:1 but since had it home its struggling..when its stood ticking over and then you set off the power goes flat to stalling if you don't catch it in time..plus started to smoke. Its ok when reving out just on set off and ticking over. Does anyone know the correct mix or any idea s. Thankyou.