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Dear Ralph: I was reading about the new Rotax 800R engine in the last issue, both the dyno run and the info on the...

Dear Ralph:
I was reading about the new Rotax 800R engine in the last issue, both the dyno run and the info on the 3-D RAVE valves. The way I read this, the 800 R is fitted with “variable valve timing”. Correct?
Peter Norton

I suppose you could make that claim about any of the power valve systems, as the exhaust port timing is varied by the position of the exhaust valve. In the case of the 800R it isn’t a matter of being simply “open” or “closed”, there is the intermediate position allowed by the use of a main valve and the smaller “fingers” controlling the sub ports, independently.

So the 800R’s three-position valve control is closer to what we could call “true” variable valve timing. Some riders think the electronically-controlled valves are capable of infinite positioning, but as far as I know they all operate on an “open” or “closed” basis, none of them utilize an intermediate positioning. Not even the servo-motor configurations. Why not? We’ll find out!

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