What’s the deal with Yamaha’s new three-cylinder?

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We do know that Yamaha has a new three-cylinder engine on the way which it’s very
excited about. We don’t know why…The engine is very important to Yamaha as it’s symbolic of a return to its old values of innovation and risk taking, areas it was stronger in than any of the other Japanese factories. Yamaha has tried hibernating through the recession but this isn’t working, the world’s economic woes are going on for too long just to hide for a while, so now Yamaha is fighting back using the weapons it’s most comfortable with: originality and technology.

So what is it about this three-cylinder engine that’s so special? We’ve been given few
clues, aside from seeing it at Cologne and former R1 designer, now senior executive
Kunihiko Miwa telling us it has a crossplane crankshaft. He says, “..this means the kind
of torque character that gives riders the exact torque they want when they need it.”

That’s cross-plane crank, zero inertial torque, 2009 R1 language, so we do know the new triple also has a cross-plane crank, and the purpose is to cut inertial torque to zero, or near as dammit.

The rest we have to guess, but these facts and some visual clues narrow the possibilities right down. Throw in some R1 technology, and a dash of T-Max to help us out, and it starts to become clearer. This is one clever engine…

There are two main possibilities, one with the outer pistons moving 180 degrees apart
and the centre one at 90 degrees in between, or the most elegant if seemingly improbable, with both outer pistons moving up and down together, and the centre one 270 degrees behind.

The T-Max crank uses a slave piston at 180 degree offset.

It’s the T-Max ingredient which makes it possible: the ground-breaking scooter uses a
slave piston for balancing purposes, but something similar in the triple would do the job
of reducing inertial torque to almost nothing. And just look at the size of that sump…
bigger than an R1′s for a smaller engine? Something’s going on…

All this engine would need now is a chunky rotating balance shaft to deal with the
primary vibes, and sure enough, there on the front of the engine, a chunky balance shaft housing. It’s not proof, other triples have balance shafts, though not usually as hefty. But, lots of things start to add up…

For the full lowdown on why I think the new triple will come with a dummy piston and
360-90-270 degree firing intervals, take a look at Ash on Bikes.

If I’m right, it’s going to sound wicked…

  • rohorn

    Interesting reading – the only good speculation I’ve read on it so far.

  • Chris

    Any chance it might be a 5-stroke?

    http://www.ilmor.co.uk/concept_5-stroke_2.php

    • http://vtbmwmov.org Eben

      I doubt it, but that’s some very cool stuff.

      It sounds like this thing should be innovative enough, though. I love seeing a new design destined for mid-displacement consumer motorcycles that would normally just get detuned leftovers from the 600 or 1000cc repliracers. Sanity may be prevailing in Japan.

    • roccopeterbilt

      I learn so much cool stuff from this site. Thanks guys.

    • http://www.postpixel.com.au mugget

      5 stroke? Why bother with that when they haven’t even got 2 stroke sorted! Build a clean 2T engine, complete with all the modern electrickery to make it rider-friendly (or rider “unfriendly” if you desire). A new generation of user serviceable, lightweight, high power motorcycles. Yeah… I’ll keep dreaming…

  • http://www.postpixel.com.au mugget

    Very interesting analysis. I sure will be keenly watching to find out what this new engine turns out to be…

  • dani

    it’s All New Yamaha YZF R6 675cc