scubaman15
Well-Known Member
Can anyone tell me why you should use 20/50weight oil in a primary case ?
I know Harley at one time recommended 20/50 but why a heavy oil when a lighter oil 10w/40 syn would lube the bearings and chain and keep the clutch plates closer together for better engagment and float the clutch "dust" off better? The only thing I could think of was that the heavy oil would not sling off the chain as easy but being it rides through the oil that can't be it? Stumped? And what about a open primary how do the bearings get lubed. Just a thought? I have been using 10/40 amsoil motorcycle syn in my softtail primary for three years and the clutch works perfect and I'm not easy on the bike / burnouts ect . What does BDM recommend?
I know Harley at one time recommended 20/50 but why a heavy oil when a lighter oil 10w/40 syn would lube the bearings and chain and keep the clutch plates closer together for better engagment and float the clutch "dust" off better? The only thing I could think of was that the heavy oil would not sling off the chain as easy but being it rides through the oil that can't be it? Stumped? And what about a open primary how do the bearings get lubed. Just a thought? I have been using 10/40 amsoil motorcycle syn in my softtail primary for three years and the clutch works perfect and I'm not easy on the bike / burnouts ect . What does BDM recommend?


