Well, the megas didn't work...

I rigged up some megas I used to use on an 840cc Triumph twin racer, they worked really well on that bike, so I was keen to see how they worked on the Commando. I only did a quick road test, I will Dyno them soon just out of interest, but the road test confirmed they won't work!

The megas open from 1.5" to 2.5" over a 12" length. Then have 12" of 2.5" perf tube.

Performance above 4 seemed better, but its hard to tell if it was really better, or just felt that way because there was a HUGE megaphonitis flat spot at 3-4k. Which meant I'd have to keep the engine above 4k all the time! Totally destroyed its rideability as a road bike!

Anyone else had any findings re exhausts on Commandos?

Faster at very high rpm, with a bad flat spot, is megaphones working.

Triton Thrasher said:

Faster at very high rpm, with a bad flat spot, is megaphones working.

Click to expand...

I know what you mean TT, and I agree up to a point, however they can be made to work throughout the range sometimes, when all of the variables line up. When I ran these megas on a Triumph racer, when compared to straight through 1.5" perf tube silencers, they gave 8bhp more in the mid range and 5bhp at peak. Peak was 7750rpm on that bike, I forget exactly what rpm the 8bhp gain was at.

In my experience, long shallow megas are more forgiving. Short fat ones are virtually impossible to make work satisfactory, even if they do give 1 or 2 BHP more at peak.