Hi everyone, I would like to ask what is the lenght of the 916 exhaust valve(21120041A)? Is it the same as the Monster ST4(21120042A)? I know the diameter is smaller on the ST4 29,0 vs 30,0. Just wondering about the lenght.... Pretty sure the intakes are exactly the same. Thanks in advance Paulo
I'm not an expert and have not measured the valves but I would expect that the S4 exhaust valves will be noticeably shorter and not interchangeable with the 916. That's because the heads are different.
Indeed they are. As it happens I have an S4 head lying around the workshop and the exhaust valves are significantly shorter than the intakes. I believe (but stand to be corrected) that the intake valves are the same length as 916 intakes and, also that 916 intake and exhaust are the same length? For the record, the S4 valves measure; Intake - 107mm, exhaust 95mm.
Paulo, both the part numbers you quote come back as 29mm valves. Be wary on the valve spec for the 916 as they used 29mm, 30mm and 31mm through the various road bike models and model years. The first one you list was used in 851, 888 and 916 Stradas
FWIW, my S4 valve diameters are exhaust - 29mm, intake - 33mm. IIRC 916 exhausts are 30mm and intake 33mm?
