one take on 6-2-6 midrange "drone"

[NCF6B]

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!

[Hornblower]

An exhaust supplier blaming drone on the windscreen... I must say, that seems a stretch. I suppose stranger things have happened but that one makes no sense to me at all unless what they're really saying is that the higher wind noise with the OEM "bagger" windscreen covers the drone noise coming from the exhaust system. OTOH, is they're saying the source of the drone is the taller windscreen then, well, it's getting pretty deep in here!

[bobbyf6b]

Well, that makes up my mind. I enjoy riding much more with a taller shield. I'd rather hear my music than have louder pipes.

[opas ride]

I test rode an F6B last September with the stock shield and Cobra 6-2-6 pipes and the drone was no different, in my opinion, that it is on my F6B that has the 11"-19" adjustable Baggershield ..., I could not deal with the wind noise and turbulence that was present with the stock shield and love my current set-up....I did notice, however, that the drone is somewhat less with the face shield up on my 3/4 HJC helmet when on the highway...Go figure......I also have talked 3 times to the Cobra people and they all have said that they have done all they can do to reduce the drone on these pipes....I intend to live with it as over time I am sure it will become less of an issue....If not, I have the stockers and they will go back on......

[NCF6B]

I spoke with a friend who rides a Harley. He said that you just get used to it if you like the sound. I guess it all comes down to what you like in your ride. I really like the sound. But then I also liked "glass pack mufflers"! It all ads "character" to your bike and individuality to your ride and to me that's what it's all about!

[Phantom]

JUST A SIMPLE TEST .....

Can someone remove one of the baffles on each side and place a electrical box round plug on the front of it (sealing off one pipe from each side of the exhaust pipes). Re-insert the baffle and go for a test ride, see if it still sounds good. NOW the exhaust gases are forced to exit through 2 of the pipes and will exit faster then before, could this help with the reverberation at cruising speeds? NEXT after the first test ride remove the plugged baffles, take a 1/4" drill bit and drill through the center of the cap placed in front of the baffle, re-insert and go for a test ride and see if you here any change to the drone and let us know if the pipes still sound good.

If the sound from the pipes is still nice and the drone is reduced, this would be a easy fix and the pipes still look good.

Someone please try this and let us know......

[Scotrod]

FWIW, Windshields can 'redirect/reflect' sound,,, Sometimes right back at the rider if the source location/angles are correct.

'Liners have the intakes pointing up under the tank. During certain RPM's (believed to be associated with valve overlap, pressure waves, etc) we had what was lovingly referred to as the 'wood block knock'. Yep, title says it all. Like 2 wooden blocks clapping together,,,

I had both the OEM shield and a Mem Shades Batwing. The OEM shield was angled/shaped/positioned just right to reflect the wood block knock noise from the airbox right back at the rider's head.

The Batwing had multiple/complex angles. Even with a shield the same height as OEM on the batwing, there was a very noticeable drop in the 'knock'

I can't comment on the 6-2-6 / windshield combination as a factor in drone as I have zero experience with that set up, but,,,, I sure as hell don't miss those clappin 2 x 4's that used to live under my seat!!! .

[edgeman55]

Well, that makes up my mind. I enjoy riding much more with a taller shield. I'd rather hear my music than have louder pipes.

Besides the more miles I put on the stock exhaust the better it sounds.I got rid of my 05 Roadstar with V&H exhaust because I was so tired of the noise.When a Harley pulls up next to me now I don't know how I put up with that noise for 6 years!

[Deer Slayer]

Ha! Here we go again. Read the cross over pipe threads. You may block it, cut it or run torque loops.

[Dfinkelsteinmd]

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.