| Alan,
the last 851s had the same size valves (33mm inlet and 29mm exhaust, I think) and cams as the 888 & 916Bip.
Bottom end components are pretty much identical, except no oil cooler as standard.
Well, mine's like that anyway!
I have a workshop Manuel if you want me to copy any of the engine pages?
I also have a book by Paolo Conti which has some good pics of the early 4-valve bikes, but they are mainly red....
Cheers, paul |