Drone in 3rd gear

SMcGirr

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So far so good with the water boxer but only got 300 miles on it so far. I do notice though a particular woo woo woo type whine in 3rd gear i.e. at slow filtering speeds. I can't get it to repeat in either 2nd or 4th at the same revs. Perhaps it'll fade as the bike runs in. Thoughts ?
 
The filtering bit was to give you an idea of the sort of speed eg 20mph ish. Now don't be pedantic! Thought that peeps would take the piss on the "woo woo woo" but it's the best I could do before my first cup of coffee.
 
Is it the paint bubbling on the rear drive ?

Oh sorry,you said 300 miles, not 3000 !!!

:augie
 
Tyres are whatever came on the bike. Dunno to be honest, anakees i think. I will check when I change my babygro.
 
Sounds like tyres to me, as the Anakees are quite loud.
 
Anakees it is, but it was hard to read the writing on the tyres, what with the shaking with the cold when I took my babygro off and all the ACF50 on the tyres ...
 
But and its a big but, out today again and if it was the tyres when I change gear to 4th but stay at the same speed the noise goes away. How can anyone explain that ?
 
It don't think it is the tyres.

I have Anakee 3s and the noise they make is higher pitched and is most noticeable on smooth tarmac - and there's not a lot of that about here :-). The noise the op writes about is consistent at about 28mph in 3rd and can be heard at similar revs in other gears but is much harder to pick out/verging on impossible unless I concentrate way more on sound than the road. I find it useful as an audible 30mph speedo.

There has been a bit of chat about this on the Boxer bit of http://www.advrider.com/
 
But and its a big but, out today again and if it was the tyres when I change gear to 4th but stay at the same speed the noise goes away. How can anyone explain that ?
Yes but your engine isn't at the same rpm. Had it myself with tourance tyres. Now on conti trail attacks which are much smoother and don't have it anymore. Don't ask me the in and out but it is a resonant frequency where everything comes together and sets this up. The same as when 2 waves come together just at the right time to make one big wave.
 
I've checked my 2015 GS today (1150km / 720 miles on the clock), and indeed, there's a kind of throbbing noise when in 3rd gear, riding at a speed of 50km/h (31mls/h).
It sounds like the 'desynchronisation' engine setting German bombers used, when flying over Britain during WW2...
It could be sound from the tyres, just nearly resonating with the engine, at this speed and revs.
Or it could be a slight difference in ignition timing at that specific engine speed...
It does disappear when driving faster, shifting up or down while maintaining the same speed....
:D
 


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