Motorcycle Repair: yamaha motorcycle, castrol gtx, necessary additives

Question
What type of oil should I use in a 1981 750 Yamaha
D

Answer
Aaron,Is this a v-twin 750 or the inline 4 cylinder? Depending on the milage you might try some Castrol GTX 10W40. Its easily purchased at most automotive stores and Walmarts.It works well on air cooled engines and provides good protection for high heat. You can go to Amsoil synthetic motorcycle oil and increase your mileage and performance but if you have any oil leaks the sythetic oil will find it. It costs more to start with but you can run a few more miles between oil changes.If you prefer a sythetic oil but cannot get Amsoil be careful when purchasing an automotive synthetic as it may not have the necessary additives to help the clutch in any way and it may start slipping.