Clutch and oil problem

[LWH]

1985 Interstate no clutch problems till 200 miles ago when I changed oil to 15-50 Mobile 1 oil clutch is now slipping and did I mess up

[rrod1393]

Not an oil engineer, but if that oil had friction additives that could be your problem. Try using a motorcycle oil or shell rotella t4 15-40 (that's what I use).

[LWH]

Ok here's what I found out, the mobile 1 oil 15w50 red label is marked SL which means it has had moly added so there I am going to drain and mix with a non-SL oil, SL is a mark for Friction Modifiers added

[Rednaxs60]

Only use oils that have an API donut with the lower half blank as per:

The lower half left blank indicates there are no energy or friction reducing additives in the oil. These older GWs were designed to use a high detergent, good quality oil with no additives, just like the cars of the day. The latest specification for an equivalent oil is the "SN" specification. Euro formulations as well as the Shell Rotella oils are good, as are the others such as Mobile 1, but the issue is to find an oil that has an API donut (it is called this) with the lower half left blank. JASO specification came in in 1999, good info but not a requirement to follow. Good luck. Cheers

[LWH]

Ok update I used Rednax advise and changed the oil and used an oil as he said, took the bike out after the oil change and within 2 miles it stopped slipping and running great now