Yeah, interesting! It seems the 3 cyl engine is becoming much more popular these days, notably in the car world too, with VW, BMW & others all either making one already or about to introduce one. The attraction there appears to be efficiency, more torque at lower revs & lower friction losses & still smooth in operation (with a balance shaft as dictated by mounting arrangements).
Besides my Legend, I'm ahead of the game here with my car a 3 cyl 1.0l Suzuki
I suppose what may be innovative with this Yamaha is the crossplane crank. They aren't giving details as yet but I'm assuming they aren't dumb enough to cod us into thinking a 120deg crank is innovative (or crossplane). So that suggests 90deg crank pins - imagine a 'T' shape, say, with the outer two cylinders making the cross & the middle one the other bit. Their engine looks like it has a balance shaft in the same position as ours. This would need to balance (as Triumph) the side to side rocking couple (1 side heading for TDC, the other BDC), plus a bit of extra metal in the middle to counter balance the up/down of the middle cyl.
The Yamaha XS750/850 (a 120deg triple) didn't have a balance shaft because the engine was rubber mounted. But as virtually all modern bikes (of a size) rigidly mount the motor in order to use it as a stressed member & save frame weight, they all need a balance shaft. (A lot more are being used in fours too for similar reasons.) So there's little more effort involved to counter balance a crossplane. (Or maybe this middle cyl can be looked after on the crankshaft itself?)
It could be Yamaha are aiming for some supposed traction advantage, ultimately in a 675cc triple supersport class, mirroring their M1/R1 fours.
But in road bikes, the crossplane may be just intended to give an extra dollop of 'character', one up on Triumph even, with their inherent offbeat firing & exhaust note. And it'll have the nice torque/power character of triples & better fuel economy compared to the usual fours from Japan.
Of course 'crossplane' also helps Yamaha to avoid the charge of simply copying what Triumph are doing.
Yeah I know what you mean there. When I had to retake my bike test after coming to Germany one of my riding lessons was a 200 kilometer Autobahn ride and I had to fill it up halfway!
That was a Honda 650 4 cylinder, (no idea which model but it was black if that's any indication ), and the engine was really screaming at about 130kmh. They're fast low down but once you get upto speed there's nothing left. I was always looking for another gear .
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