Have a 1983 R100 Dual Pluged18K.When I first checked the timing it was off,so I set it to "S" not knowing that it should(?) be advanced to close to OT.Bike ran very good 35mpg w/a sidecar.Researched and reset the timing as per Snow Bum.Idle went up,readjusted,used vac gauge,Have hesitation at take off,poor starting,and can't seem to balance right.A new idle jet is mentioned.Question; Can I go back to the "S" timing,what are the pros and cons,is there any problems with that? Somewhere in Alaska!