Kawi2strokes.com Forum

On the vibration I was concerned about this when I built th kaw and the 180 4 is not bad for vibration (bloody awful for surge) How would this really feel on a street bike. ? I mean would it be bad like an h2. And sorry what's crank whip

180 has cancelling firing, 1/4, then, 2/3, etc. Vibrations created on each end cancel each other for the most part.

The 90 degree engines have 1, 2, 4, 3 firing. This sets up vibration on one side of the engine, goes to the outer end of the other side, and creates an opposite vibration, then repeats, etc. Water in a jar would raise on either side, then down, and middle would lift, fall, over and over, cancelling vibration.

If you can imagine this, if you had four hands, and all were in front of you, both outer hands would lump up and down together, then, when the outers were down, the two inners would be up, then alternate, fairly even, not a lot of "vibration", this is the 180.

Now, same four hands, left outer, left inner, right outer, right inner, repeat, it is like a wave of liquid moving back and forth in a jar, left to right, then again, left to right, all with one operation between the sequence, but more violently, and no cancelling of pulses.

This is a way too simple answer to a very complicated situation of firing pulses.

You think it would make much difference depending on the firing order. I'm figuring I'll have to use 1324 or 1423 mine will be 2 180 cranks. Sounds like power production or quality wasn't an issue or at least not much. Either of you have experience with o ring heads. Seems to be highly recommended on the yamahas. Even the air cooled ones.

As was said, Honda tried it, and they ain't skimpy in the engineering department, and only used it one year, with a great deal of rider and mechanic consternation of it. Even 56 degree "big bang" 4 stroke V4's use a 180 degree firing order. ALL the two stroke V and Square 4's used the 180, some were tried with the re-phased 90 degree, in various configurations of firing order, and ALL went back to the 180 degree phasing.

My brother raced an '84 RZ350 Yamaha, it was 180 firing of course. We noticed the cranks were splined together, so pressed them apart and then back together as a single, wanting better traction hard over in a corner. We found Yamaha had balanced it as a pair of cylinders, not as two individual singles, and it vibrated so bad we put it back again.

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1974 Kawasaki H2B 750, 1981 Yamaha XV750 Cafe, 1986 Kawasaki KDX200, 2003 Honda XR100, 2004 SDG140. 2006 Ninja 500R Turbo intercooled fuel injected.

You think it would make much difference depending on the firing order. I'm figuring I'll have to use 1324 or 1423 mine will be 2 180 cranks. Sounds like power production or quality wasn't an issue or at least not much. Either of you have experience with o ring heads. Seems to be highly recommended on the yamahas. Even the air cooled ones.

Sorry for the double post. Any thoughts on the o ring head seal

O rings work great. The machinist needs to know what they are doing to get the correct squish. I have never had trouble with gaskets, so i don't bother.

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Twist the throttle, tilt the horizon, and have a great time. What triples are all about...........

U know the specs? O ring and groove

Back when there were two stroke 250's used in flat track racing, the Suzuki X6 Hustler engines were the ones to use, with one critical mod, they became Twingles". The crank was rephased to fire both cylinders together, making the twin-single.

When I hung out at the late Jeff Bratton's crankshaft shop decades ago, I built a couple of H2R cranks for Erv, they were phased to fire as a "TRINGLE", all 3 at once, for his flat tracker H2R engined bikes