Speaking hypothetically,,,,,
#1
A “friend of mine” who has just recently bought a Hayabusa has, on two occasions now, taken his ‘bus out to ‘stretch it’s legs’. At around the 285-290kph mark, my ‘friend’ experienced a sudden shuddering in the helmet area, an experience not unlike being attacked in the head by a construction worker wielding a bloody great big jack-hammer.

After the first instance, my buddy put the whole experience down to possibly not having the chin strap on tight enough, and went out to try a second time with the strap on so tight, my (errr, his) eyeballs were popping out.

On the second run, (knowing what to expect), ‘he’ was a little more prepared when the shuddering returned and took a little more time to observe that the shuddering was also felt going along his back. It almost felt as though there was an aerodynamic anomaly going over the causing the airflow to reverberate (imagine someone trying to massage your back by using two meat tenderisors). – a very technical expression, I know.

Has anyone else had ‘a friend’ experience this type of thing? Any thoughts about a possible cause (I’ve thought of (a) poor rider position, although ‘he’ was completely tucked under the screen when it happened, (b) helmet design, or © fecal matter interrupting the bike’s airflow as it rushed out the undies.)

A few stats are:

Rider – 90 kgs, short (5 ft, 4 inches) – interpretation – Fat Bastard,
Helmet – AGV X-Vent,
Road – Long, straight & smooth (hey, when the opportunity presents itself,,,,,)
Cross winds – none on the day,
Rear seat cover – on.
Bike – stock standard.

Alternatively, anyone else had the same (or similar experience?).

Cheers,

Cruzabusa.
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#2
Had the same thing, my head was vibrating so much I think my eyeballs were bouncing ! An aftermarket screen might be in order ?
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#3
Errr... my 'friend' couldnt tell ... he was too busy trying to hang on for dear life!!
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#4
Yeah I've had that. But I put my head up more into the slip stream and it stopped. Probably just trailing edge turbulence off the fairing and onto the top of the helmet. Stick yer head up more and your getting straight airflow and the turbulence isnt going over the top of the helmet and 'bouncing'it in low/high pressure peaks and troughs but is just ploughing around it.

paulh
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#5
Tell him to go faster
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#6
I'm 88k and 6" and like Paul, have found adjusting my body position (particularly my elbows for some reason) makes all the difference.

It was suggested to me that thicker cheek pads for my helmet may also help. Arais have detachable cheeks pads and you can buy different thicknesses for them. The ones I bought are each 1cm thicker than the standard size in an XL helmet. Haven't used 'em yet. I think they are sitting at the bottom of a cupboard somehwere upstairs.

-Guy
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