Just took my second ride on my new, bone-stock Thruxton. On a right-hand sweeper at modest speeds - maybe 60 mph - we hit a series of bumps that threw her into a rather interesting head shake. She waggled the clipons back and forth maybe three or four times, then settled down.

I've been riding sportbikes, sport tourers, and dual-purpose bikes for about twenty years and have never experienced anything like this. Other than this one incident, the Thrux has generally seemed pretty well planted.

Has anybody else experienced this bump-induced head shake with their Thrux? I gather steering dampers are often installed as remedies for head shake on sportbikes, but that seems to be more for speed-induced issues. This seems to be related to road surface.

TIA for any help.

-Birdo

I had the same problem and found two solutions.

One - tyre pressures...from the garage they were low and I put 33 psi in front and back but then changed the the back to 38 psi which helped.

Two - I changed the suspension settings as per the owners manual for a firm setting...front 2 notches and back 3 notches.

I haven't had her shake her head since firming up the suspension and it does feel firmer and better.

John

The wobble has been noted by a number of riders. It has happened to me three times - each on rough surfaces in a sweeping turn. Thats the bad news. The good is the wobble is not severe, the Thruxton remaains stable and it is of short duration. BVoosting the tire pressure by 3 or 4 psi helps. I'll try Irish Johny's suspension remedy as well.

HGE

Putting Ikons on the rear and cranking down the front preload virtually eliminated the trait in mine.

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vikingdrvr

Thanks for the suggestions. I'll try the tire pressure and preload adjustment and see if they solve it.

-Birdo

My BonnieBlack shakes it's head when I take my hands off the bars and let'er decelerate.... did it all weekend. Only had one bump induced head shake: I was riding with only one hand on the bars, hit a BIG hole, and she was a little upset by it all.

I've been running 34 up front, will try running 38 as suggested.

Likely, I'll be buying a steering damper though. I run heavy bags on the back, thereby putting the weight bias more on my rear wheel (lifting my front?).

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- 'Rider' -

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I've said this many times on this group and others:
If you think you need a steering damper on your road bike, something else is wrong. Find the problem and fix it.
Using a steering damper is like turning up the radio to mask tranmission noise in your car.
Suspension and tyre pressures need to be matched to your weight, your luggage weight, the distribution of those weights. The 'factory' settings and manual recommendations are guidelines. Play with the adjustables and find what suits you.

Pete.

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Pete.

Do as you will, but harm none.

I dont want to argue with Pete about this, he seems adamant. I'll agree with him that tire pressure and suspension should likely be adjusted from whatever the current settings are if this seems to be occurring regularly.

But in the case of encountering pot holes or other irregular road hazards, a major deflection of the front end can occur regardless of whether the bike is set up properly. And can lead to disasterous results particularly if you're riding one-handed for a moment (adjusting your shield, scratching your arse etc.) The damper can help prevent this. This isn't my opinion of the theory of motorcycle physics, just my experience with riding bikes with and without dampers installed.

There is one completely wrecked Thrux in Dallas right now (dont know the owner) due reportedly to a head shake problem which oscillated beyond his ability to control. I've had that happen once so violently at Texas World Speedway coming off the banking that it shook my feet off the pegs. Wheww!!! It ain't fun.

[ This message was edited by: kwajazz on 2005-11-21 16:16 ]

I've read before from knowledgeable guys elsewhere, that modern bikes, with modern wheels, and modern suspension....... are flawlessly PERFECT and in no need of the steering dampers, STILL marketed (by the way) for all sorts of street bikes.

Why are there steering dampers on modern Japanese high speed crotch rockets?
Why did they put one on both the new BMW K1200's and the soon-to-be-released F800S?
Why do the Triumph Bonneville THRUXTON racers put them on their stock bikes (save for shocks & exhaust)????

WHY?

I've had 14 street bikes in the last 35 years. NONE of them felt like they were in need of a supplemental steering damper, TO INCLUDE my Honda CL360....... that gave me a head wag, brown shorts, and one hell of a surprise!

My Bonneville wiggles it's head when I sit up and ride with no hands on the bars....... It's given other indications that it's in it's nature NOT to be "perfect"........ I will increase my air pressure from 34 up front to 38 as advised, BUT I will still be installing a steering damper anyway...... if not at least for the "cool" factor.
:-D

Again,
WHY THEN DO THE THRUXTON RACERS RUN A STEERING DAMPER? Surely THEY know their ****e!?!?!!!!!

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Watch a MotGP race or an AMA Superbike race and you'll see why steering dampers are used and also what causes them to be necessary. If the front end is light (due to stupendess amounts of HP) and you hit a bump that causes a steering deflection, the oscillation, "Tank Slapper" is enivitable... unless of course you have hydraulic elbows.

Cheers, Cyn-

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Cheers y'all, Cyn-
Experience is a cruel instructor...
First you take the test,
then you learn the lesson!
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