crossover pipes

[henzilla]

Have read the reasons for crossover pipes on dual exhaust engines. Many opinions and a few myths abound as well as the engineer speak one would expect as the definitive reasoning.

Just an observation on a R1150R header, which is a two piece,I had off yesterday and wondering if the 1200's have this reducer inserted ? I bet most thought it is a wide open channel on the 1150's. Just one of those engine-ered tweaks I thought about seeing this. I had seen this reducer before,but never gave it much thought as it must do what is was designed to do. It certainly restricts flow between the two exhausts.

 

[20774]

Steve -

I'll throw this out there... On the manometers that people build to synch carbs on the Airheads, usually people put pinchers or snubbers on the plastic hosing in order to reduce the effect of the pulses. If not, then the water/oil is bouncing all over the place. When the orifice is closed down, that effect is greatly reduced. Maybe the reason is to allow flow of air but not large pulses.

 

[pauls1150]

Typically, hole size is determined by how much spent fuel one needs to expel in how much time...
but that looks like a real over-kill, especially considering the restriction of the catalytic converter just downstream.
Additionally, any restriction "up close" is going to be a major hot spot... I'd be so tempted to drill it out a bit...

 

[BC1100S]

Just an observation on a R1150R header, which is a two piece,I had off yesterday

Same thing on 1100S.

 

[henzilla]

Same thing on 1100S.

I was thinking the 1100's maybe did as well...had them off before, just don't remember looking in the cross pipe.
Since the 1200's we have are one piece, guess I'll run a fish tape in them to see if it continued on that model someday. Just curious I guess