[Desmo Elmer]

Crossovers are great -- provided the exhaust flow (CFM) going into the crossover itself is about the same and out of phase. Problem one runs into is that with differing flow rates and the cylinders being out of phase, you can get some really strange things to happen ala one cylinder scavenging incredibly well and the other really poorly in a poorly designed system. Thus a crossover itself isn't always to ones advantage.

This is interesting info Mark. I've been kicking around the idea of a one low exit, one undertail exit set-up for my M800. I thought I brought this up somewhere else on this board, but I'll be danged if I can find it now...

Seems like one could get very near to equal length headers that way, but my concern was whether or not a crossover would be necessary. I've seen crossovers on inline twins with identical dual exhausts so I presume there is more to it than just "equalizing" disparate header lengths. Are there any good theoretical sources out there you'd recommend reading?

 

[Desmo Elmer]

Thanks Mark,

Per crossovers?

No, I meant front header/can exiting low near the front of the rear wheel and the rear header/can going right out the back under tail. Two discrete header /can set-ups. I couldn't imagine how one would stick a crossover in a system like that. JUst wondering if a crossover was necessary...

I don't use them at all on my DesmoDevil BoomTube exhaust systems.

That's the answer I was looking for. I don't like loud, so back pressure will be par for the course in whatever I dream up.