Ok. Thruxton/T100
Inlet open 4deg btdc. close 48deg abdc duration 232deg
Speedmaster 865
ahem...ZERO deg btdc 24deg abdc wahey! 204deg
Thruxton/T100
Exhaust open 33deg bbdc close 7deg atdc Duration 220
Speedmaster 865
open 39deg bbdc close 7deg BEFORE!!tdc (recheck the inlet opening figure gentlemen - Briggs and Stratton have more bleedin overlap - really!) Duration 212
So there you have it - factory figures. The book quotes the lift as 9.5 and 9.4 respectively for inlet and exhaust for both models, first one we measure that actually does that will be the 1st - they dont even do that much.
Rather underwhelming to say the least, and lots of potential for some valve lift and duration
Watch this space....
