one take on 6-2-6 midrange "drone"
I contacted technical support at Cobra regarding the mid-range "drone" that some people have discussed and I have experienced with the 6-2-6 pipes. The technician I spoke with attributed the "drone" noise to the installation of a higher aftermarket windshield which affects air flow. My experience is that the noise is significantly reduced as acceleration through the gears reduces RPMs. He said all of their tests were done with the OEM windshield. This may point the way to some solutions for those who prefer not to have that noise. Any thoughts appreciated!
Cheap fixes for the drone
Like many other F6B riders, I have removed the baffles from my Cobra 6er's and noticed the drone at 2900-3200 rpm, especially on the highway when there is an overpass or high wall on the side of the road. Because I love the sound of the pipes at idle and under hard acceleration, I simply avoid the "drone range" by watching the tach. I also installed the shorter Lee Bailey windscreen as I like to feel and hear the wind more than the stereo at higher speeds.
Functionally, it is very easy to stay over 3200 rpm in the right gear in most situations that we encounter here in NorCal where the twisties can be managed in 3rd or 4th gear and the highways always allow a brisker than posted speed. This is good because the 55-65 mph range puts me smack in the middle of the "drone zone, or DZ in OD, so I just downshift until I can break out of the traffic jam that keeps me in the DZ.
Unless someone discovers a DIY fix that is cheap, I'll just burn a little more gas by keeping the rev's up and the drone down.