Firing Order

[FJ1200W]

Kawasaki H2 Supercharged is 1-2-4-3
While I do not see it happening, I'd like to own one of those someday.
Wouldn't the "normal" tri-Y design for this be 1-4 and 2-3 then into one, rather than the 1-2 3-4 into one that seem to be the norm?
Or 1-3 2-4 just to muddy this ancient old post?
Happy New Year!

[Pat Conlon]

Steve, yep you are correct....the best Tri Y header tube design for the gas scavenging on our FJ would be have the #1 tube merge into 4 then #2 merge into 3. However you can't do that and keep your primary tubes equal length.
Long time ago I saw a Tri Y FJ header with the #4 primary tube crossed over the #2/3 and merged with the #1 tube...it looked weird as hell.

[RPM - Robert]

Sure you could, Pat. A couple loopy loops here or there and your back to equal length

[FJmonkey]

I think the Blueman Group made a few versions as well.

[FJ1200W]

I'm pretty sure this was my "gateway" exhaust.