Ducati Monster Forum

I ride an 02 620, the other day i was leaning the bike on a fairly tight overpass going a bit over the speed limit, not really sure what happened, but all of a suddend the front of the bike started to "speed wobble" not really sure how to describe it, it was shaking alot.  I think there was some un even payment just before this happened.

this totally freaked me out, but i just leaned a bit more and gave it more throttle and it seemed to steady it's self out.  What would this be caused from, poor suspension ? bad technique? too fast ?   Would a stearing dampner help in this situation? Would it be a good modification to get? this is the only time something like this has happened to me. I've been riding for about 3 years now.

If my front gets light (bump, uneven pavement etc can cause this at speed) it'll wobble a bit.  Usually a speed damper helps.  If you've got stock suspension, suspension work would be a better investment ~

JM

There's a chance you suspension needs some help - but sometimes this just happens due to circumstances.  A steering DAMPER would help, but you also want to be sure it's not just masking a suspension problem.. Though it doesn't really sound like you;ve got problems.

Your instinct to give it more throttle was a good one - letting up can actually make it worse. 

yes it's just stock suspension, and i'm probably a bit over weight for it at 185lbs.  I heard of GSXR forks swaping in, i'll have to do a search on that mod, as it might be a good mod to do.

This is (possibly a mild case of) a 'tank slapper'.  I'll leave it up to you do a google search for what makes them occur but there's not really a cure, just products and techniques which can minimize their occurrence and help you ride them out.

The term is "headshake".  He would have crashed if it had progressed to the tank slapper stage.

Headshake is normal for aggressive riding.  It's when the bars wiggle a little, but you're not really out of control.  If you're accelerating while going uphill over bumpy pavement it's almost guaranteed to occur.  Usually it is corrected by changing the weight on the front tire by either more or less acceleration.

A tank slapper is when the bars are swinging violently back and forth from full lock to full lock.  Most people don't recover from one of those.

When you're straight up and down, any bumps in the road are absorbed by your forks and shock, for the most part.  When leaned over, the bumps are absorbed by those two components, plus your steering head and your frame.  If you hit a bump in a turn, you're going to get a certain amount of head shake. 

The way to smooth out head shake is to let the bike work itself out.  Remove as much input as possible from the bars, make sure your elbows are relaxed, and give it gentle throttle.  Never try to even out head shake with force, since you will only make it worse.  Make sure that your riding position has your tush as close to the tank as possible (sorry guys, but I know this isn't as comfortable for you).  It will help make your front tire contact patch, the one that's responsible for steering and braking, larger.  It will also help you to keep from having the front get light enough to lift. 

There was a great article about tank slappers and head shake in the March 2008 issue of RRW.  It includes how it feels, how they happen, what people do that make them worse, what you can do to make them better, and how to prevent them from happening in the first place.

Thanks for all the tips and comments guys and gals

Sounds like it was a mild tank-slapper. 

A tank slapper is a rapid, high intensity and unwanted motion of the handlebars back and forth.  Literally it is the slapping of the bars from side to side that can get violent enough to actually hit the tank of the motorcycle, hence the name “tankslapper.”  The bad news is that they are scary as hell and can cause some pretty nasty crashes.  The good news is that there are some very effective techniques you can use to handle them.

What causes tank slappers?

The suspension system on a motorcycle is designed to make the ride more comfortable for the rider and primarily to keep the tires in good contact with the road surface which can include bumps, cracks, pot holes and all manner of imperfections.  This system must work while the motorcycle is straight up and down and also during turning when the bike is leaned over, sometimes at very extreme lean angles. 

In his book, A Twist of the Wrist II, Keith Code explains, “the process of head shake (which can be the beginnings of a tank slapper) begins when the tire hits a ripple and, along with the suspension, compresses. This throws the wheel slightly off-center.  When the suspension and tire release, the wheel is light and flicks back toward a centered position, but again, slightly off-center.  Still off-center when it loads again from the next ripple; again it is flicked past its centered position.  The cycle of flicking back and forth repeats as the front-end seeks to stabilize through this automatic and necessary self- correcting process. Any bike will do it, and what most riders fail to realize is that this shake is a necessary part of the bike’s suspension system.” 

The little wiggle in the front of the bike is how the motorcycle self corrects and gets itself back on track. Ever see a motorcycle race where something, either a tank slapper or a big slide causes the rider to either be ejected from, or fall off the bike?  As soon as the rider is no longer on the bike  it wiggles a bit, straightens out, keeps on going perfectly straight until it runs out of momentum and falls over.  This is a classic example of how a bike, if left to its own devices will sort itself out.  Code mentions that, “based on the amount of wiggling, squirming and overuse of controls most riders exhibit, the bike would, if it could, surely ask them to leave.  Riders create instability on their own mounts.” 

Head shake can be caused by hitting a bump or a ripple in the pavement or it can occur when accelerating hard out of a corner.  Hard acceleration can cause the front end to get light or even wheelie which means that the tire is no longer following the road very well, and when it touches back down it can skip or bounce or be off-center, starting off the headshake.  Code explains that, “the good news is that if your bike is basically tight (steering head bearings not excessively worn, forks and shock not sticking etc.) the head-shake stays up front and does not transfer to the rest of the bike.” 

Eventually, the oscillation will die out on its own, unless we interfere. 

Riders tend to interfere by tensing up and making the situation worse.  What MonsterDark did by staying relaxed and continuing to apply the throttle is one portion of the CURE for tankslappers.  Anyone else had one?  What other things can you do to "save yourself" from a tank slapper?

Misti

Misti!  Welcome over to the DMF.  Good to have you here!

Misti, [laugh] ripped off your own article!

Well you pretty much covered it!!  [thumbsup]

I have had a few nasty headshakes while throttling out of turns, and lightening up on the bars usually takes care of it like everyone already said. When you "deathgrip" the bars in panic, it transmits the shake to the chassis. Not good!! Having your steering damper set at too high of a resistance can also do this, so be careful not to have it set too stiff. You shouldn't be able to tell its there when steering the bike at a standstill.

Basically, you wat to remain "as invisible as possible" on the bike. Like Misti said, a bike will always want to correct itself and continue on its own; It's when the rider interferes that the bike gets upset. Riding a motorcycle is basically the process of continually interfering with the bike to get it to do what YOU want!!

Had the same thing happen to me...

Coming out of a long sweeping merge that was just repaved, the road dropped 2-3 inches from new pavement onto old.
The front end got light starting oscillating and then eventually threw me like a rag doll for a full high-side at 70mph.

landing on my helmet and elbow snapping my collarbone. and then proceeded to slide and roll for a bit. luckily everyone behind me saw my ragged-andy imitation and stopped.

But the tank slapper ripped open the steering head, ever seen metal tear like paper?!

some people told me i should have put on throttle, some said shift weight forward some said nothing i could have done.

But i do know that when i called the factory about the situation and the weight distribution on the 99 Monster, the guy i talked to had the SAME tank slapper that broke his collarbone.

Someone in this thread asked if anyone else had any stories of occurrences-I DO, I think. lol   
I was quite the noob (still technically am), hubbi and I were on nice longish ride, and me on my Ninjette. We came around bend to side of a lake and I already had some "issues" with winds on prior rides, so got little tense, knowing that open lake to right on this particular day would fer SURE come with winds-BUT, I DID relax, psyched self to do so....It had also rained bit earlier-not sure how much, so roads were wet of course.  Sure enuff, gusts came off lake from right, but I RELAXED for change.  We were cruising steady, speed limit, maybe just 50 MPH tops and suddenly another of many gusts came, this time a WIERD one.....came really LOW, could feel it hit left front tire and THEN got more wierd (Or I DID something to CAUSE it?) anyways, felt it work it's way BACK, thru bike...when it hit front tire, felt LITTLE wiggle of tire...then felt like whirlwind working way thru bike LOW again to back....or, was this a WOBBLE? Hydroplane??  ANYways, scared the HELL outta me, but hubbi up front and had no clue.....I just stayed neutral....no throttle increase or decrease, pretty sure did NOT death grip bars, stayed STILL and centered on bike and it was all over. WHEW! Caught up to hubbi at stop light and trying to stay calm, but really just wanted OFF lol! 
I am a VERY small person (even confused for a "little kid" on Ninjette just last week-seriously) and been concerned I am TOO LIGHT even for bikes, but in this case, from what I have read, this may have been just my saving grace-I WUZ "invisible" on bike as suggested above????   
Would LUV to know what happened, HOW it happened, WHY it happened, did I do RIGHT ETC...drove hubbi NUTS for weeks after this-He simply put it :"You obviously did SOMETHING right, you did not wreck!".....hmmmm   
Sorry about small novel here, but anyone HAVE a clue?  I am in process of buying used Monster DARK this week-SO excited...feels like perfect bike for me all around. Tks!