I'm contemplating building a custom 2 into 1 exhaust..
Would a factory chamber be sufficient or a larger custom expansion chamber be needed?
dont.
ive seen it work once on a twin, fairly well. but the belly was HUGE
Roger at Wicked ATV is working on a 2 into 1 Banshee pipe.
To paraphrase, he expects to lose a few hp up top but hopefully a strong low end and midrange.
He's on FB at https://www.facebook.com/Wickedatv
(https://i.ibb.co/s1KMMCH/Wicked-2-1.jpg)
common on snow machines , two work better though
I've wanted to try the K2tecs for a long time.
2 into 1 pipes on a Banshee sound wicked. Kinda like a nascar.
Fitting a bigger dia pipe can be a bit of a pain if you still want to have any cornering clearance.
My pipes are significantly fatter than most and I had to add a lot of bends to fit them tight right under the frame.
3 into 1 pipes on a GT750 sound way better than any individual chambers but do loose a bit of top end and when I say a bit, I mean like 40%.
That said, sleds use single pipes and worked pretty well but they tended to be huge diameter and being a sled with CVT, they didn't necessarily make good low end power. There was a long thread somewhere about a guy who built a 2 into 1 RZ350 system but IIRC he could never get it to make close to the power of individual pipes despite what the software told him.
Sleds typically have very short headers in their 2 into 1 and 3 into 1 systems which probably helps to minimize some of the harmful return wave timing.
How about running it as a twingle with a 360 degree crank? That would alleviate some of the exhaust timing event issues but it might shake a bit