Hi all. I have a 1986 yfm 80 yamaha moto 4 four wheeler i jus bought. Runs fine. Idles good in neutral. When i click the gear shifter up into gear 1-4 it wants to automatically take off going forward. When it should sit still untill i give it gas. Not sure if previous owner messed with the clutch or not. Tryed to adjust the clutch adjustment no help. Any ideas?