I asked the difference between MC-1 and H1-R a while ago and never got a good answer. I have a DA 100 just finishing break in and I am going with the MC-1. Only reason is I read that long test someone did on here and the H1-R ran hotter (before needles were adjusted) and it burned more fuel. Since a lot of guys have been running MC-1 for a while I decided to go that route. DA said either Bel Ray was fine and when I called them, they said the same thing, whatever oil you use, don't use KLOTZ. They didn't give a reason, just said to trust them on that. I think others on here though have had success with KLOTZ so who knows!