[hillbro]

I have been wanting to post this for a while but just now remembered when I was at the computer.

The other day I pulled a bonehead move and I am now here to talk about it so other rides like me are educated. I was in a hurry pulled out of my neighborhood on the main road in first gear and from about 35 - 70mph went full throttle.

I suppose my knee / wrist pressure / death grip on the handle bars is all wrong (as describe in Keith Urbans Twist of the Wrist II) and I started getting a REALLY bad head shake from the bike. It was so bad the handle bars were actually turning all the way left and all the way right while I was going around 70-80mph. It also felt like my bike was bouncing up and down. Keep in mind I was still accelerating while this was happening. I thought maybe lifting the tire would help (I had never experienced this before)

When it got REALLY bad I completely let off the throttle and immediately the handlebars stabilized and the bike was under control. It caused me to go over a little into the left lane (two lanes in each direction thankfully) and in my mind I thought "Without a doubt I am going to wreck right now"... So relieved when I luckily saved it.

I ride an '18 GSXR 750. Sold my 07' GSXR 600 4 years ago so I took a bit of a break. I always heard there isn't much of a power difference between 600s and 750s and I actually disagree. Perhaps it is just weight distribution, but my front tire gets REALLY light (floats almost) in first gear with full throttle.

Anyway, I always thought tank slap was when you drop a wheelie hard and you smash your balls into the tank... I didn't realize its actually really bad headshake... I have gotten light cases of head shake in first gear acceleration because my tire just floats and I assume I hold the handlebars too tight instead of my knees.

On the video below if you skip to 2:46 that is similar to what happened to me except mine seemed like it lasted a lot longer (see below). Be safe and be educated!

[ame]https://youtu.be/ufjKCbmrgGw?t=2m47s[/ame]

 

[FlipFlop]

Winger goes into wobble mode at anything above 80mph and even then if I am not very ginger on the bars it can go into it at over 70. otherwise I can take my hands off the bars and cruise so I am convinced it has to do with the very large heavy fairing on the front end.

 

[Porky]

Take the bike back to the dealer and tell them it speed wobbles! There is a nefarious reason why this is happening to you. The GSXR series of bikes are well sorted out and shouldn't do that---unless you took your hands off of the bars:surprise:

Doesn't the '18' have a steering damper?

Sam:surprise:

 

[vistavette]

Although old this is a great video:

Sent from my Nexus 6 using Tapatalk

 

[WintrSol]

Take the bike back to the dealer and tell them it speed wobbles! There is a nefarious reason why this is happening to you. The GSXR series of bikes are well sorted out and shouldn't do that---unless you took your hands off of the bars:surprise:

Doesn't the '18' have a steering damper?

Sam:surprise:

In my years of riding, I've never had a bike do this. My 305 Super Hawk came with a damper, which did nothing, so I removed it - still no wobbles or other unstable conditions, even as close to redline as it would get (~97mph).

 

[joewasaki73]

absolutely excellent video, vistavette; glad i watched it. thanks.

 

[BWB75]

Scary tankslap video! I watched it full screen, too. Yikes!

I have never gone full throttle on my current motorcycle. Pretty sure I did on the Sportster, and certain I did it on the Kawasaki EX500. Never had any wobble or weave. Looks terrifying!

 

[PP1]

Holy cow.....I've never even heard of that. Would be cleaning my shorts for sure.

 

[JAM1968]

I only encountered it on one of my bikes through the years a 1983 Suzuki GS650. It is very scary.

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[cc rider]

The country singer is doing motorcycle videos now ? LOL you said keith urban. But, seriously, you're front tire is light in first gear at full throttle?! Uh, yeah, its a wheelie machine not a cruiser. 1st gear full throttle is lot of power to the bike. How can you not be looping it or are you talking at high speeds in 1st?
Sometimes guys panic and put a death grip on the bars. Last thing you wanna do cause u r fighting the bike (before or after a tank slapper). My 13 cbr 1000 comes with an electronic damper/stabilizer. Its great till higher speeds. Then steering gets too tight. Im assuming you have one on yours.
Could have been worse. You could have been this guy:

 

[ketchboy]

There are only two reasons for a tank slapper. New rider, or something is wrong with the bike. So let's assume something is wrong with the bike. Pull your front end down, check your neck bearings for pits, loss of chrome, dirt, whatever. Grease the upper and lower bearings. HEAVY grease, not some universal lightweight ****. Wheel bearing grease will do. Tighten up the neck bearings, loosen, and then tighten again. Once assembled, check your 'fall off'. Once that's corrected, get rid of the 'fish oil' in your forks and put in straight 20wt oil. Properly set up, you will not have any wobble, or need a stabilizer.

IF you're a new rider, or have not experienced the thrill of a wobble, slowly ease off the throttle, stick your feet out to catch some wind and stabilize the bike. Once under control, you are on your way.

Neck bearings should be part of your annual maintenance!

I went thru a lot of wobbles until my riding partner (much more experienced than I) told me and showed me what to do. And this was back in the 70's! It worked then, and it will work now. I just finished up my 81 Suzy gs1000. Took it out and let her rip. I mean HARD on the throttle, up to 100 mph. No problems.

Before I found the 'cure', I had my Honda 750 (highly modified by Youshurmia) up to 150 on the speedo and got into a wobble. You can get out of it. Just ease off on the throttle and stick your feet out to stabilize the bike. Then fix the damn thing.

 

[Porky]

Good advice but his 2018 Suzuki is practically brand new so steering head bearings probably don't need to be cleaned and repacked at this time. The tension may have to be adjusted though.

Sam:nerd:

 

[ketchboy]

Good advice but his 2018 Suzuki is practically brand new so steering head bearings probably don't need to be cleaned and repacked at this time. The tension may have to be adjusted though.

Sam:nerd:

Very true. And I agree....sort of. Dirty? No. However, it was assembled by a person. And that person may have not done his job right. Just a thought. Proper fall off will tell if the bearings need to be tightened. I'm getting into areas I don't understand here, but a leading axle with too much (trail?) might have something to do with it also. I don't know if you can do this with the newer bikes Porky, but I used to, and still do with my bikes, is loosen the triple trees and drop the forks down one inch. It makes a big difference in handling. Plus it makes the older bikes more stable.

 

[cc rider]

That's not true. How would you explain the ones in Moto GP? They happen in professional racing sometimes. I think it tends to happen more on the track than street cause of the way the bike is used (pushed to it's limits).

There are only two reasons for a tank slapper. New rider, or something is wrong with the bike.

 

[vito]

I've never encountered this problem, nor had any front end wobble in 35 years of riding on multiple motorcycles. As to the cause being a heavy front end fairing, that doesn't seem likely. The front end on my 2016 Goldwing is about as heavy as on any bike, I would guess, and the bike stays rock steady at any speed that I have ridden it, up to about 110 mph which is as fast as I've had this bike. Cruising on the Interstate at 80 I get zero vibration in the mirrors and could ride without my hands on the grips if I wanted to without any problem.

 

[Offcenter]

The previous owner of my Goldwing 1500 said that in the 17 years that he owned it, he was never able to take his hands off of the bars. It would start to wobble immediately.
He had used Dunlop E3 tires on it since it was new.
I removed the damned Dunlop E3 tire from the front and replaced it with a Michellin Commander II.
Presto! No more wobble. I can take my hands off of the bars at any speed.
I did it while riding with the previous owner of the bike and he was amazed.
The Commander II now has about 10,000 miles on it and the bike is still steady as a rock.
Sometimes it's the tires, not the steering.

 

[ketchboy]

cc rider, and offcenter.....and anybody else, for that matter. I have a bad habit of making an opinion seem like a statement. Sorry if my post seemed like the 'end all' of wobble problems. It's obviously not.

I too, have done the same thing as offcenter. Terrible wobble, years ago on one of my bikes. Changed the tires and everything cleared up.

As far as full out racing goes, I agree that the bikes are tuned to the max and still have handling problems. Yes, they are pushed to, and beyond the limits of their design.

I am far from any kind of engineer, I just work under my shade tree with a Bourbon and Water, and try different things. (Most don't work. lol) However, I will say that what I described in my previous post, worked for me. I read somewhere that high speed wobble also has a lot to do with the harmonics of the engine against the frame. Remember, the engine is doing it's best to jump out of the frame and escape. Only the motor mounts keep it there and they absorb the vibrations. Those vibrations are transferred to the frame. Once those vibrations increase to a certain level, over time, some bikes end up with cracks around the motor mounts, or simply break, if not taken care of. The weak spots are the front of the bike, and the rear. Professional Engineers say they know what it is and have been trying to correct it for years. And yes, they have made tremendous progress thru suspension, tires and frame design. But it's still there.

But like I said, heavier fork oil, greased neck bearings, and having the neck stem tightened down to the proper 'fall off' should take care of most problems on a normal street bike. Remember, that's just my opinion from having gone thru it.

 

[cc rider]

I don't think it's that they have handling problems. Its a traction issue. Yes, they are tuned to the max. They probably spend just as much time tuning suspensions. That is huge in pro racing. You can bet the house that their isnt anything wrong with those bikes before its put on the track. They spend millions on teams to make sure of that. In addition these are mutli million dollar machines, not 20k. It's just a matter of how some of these guys ride. On their elbows, a strand of rubber, etc. I'm surprised it doesnt happen more often.

cc rider, and offcenter.....and anybody else, for that matter. I have a bad habit of making an opinion seem like a statement. Sorry if my post seemed like the 'end all' of wobble problems. It's obviously not.

I too, have done the same thing as offcenter. Terrible wobble, years ago on one of my bikes. Changed the tires and everything cleared up.

As far as full out racing goes, I agree that the bikes are tuned to the max and still have handling problems. Yes, they are pushed to, and beyond the limits of their design.

 

[Offcenter]

When you think of just how much gyroscopic force is generated by those large heavy wheels, it completely amazes me that they EVER wobble AT ALL.
You would think that gyroscopic force would even make it difficult to steer.

 

[Miss Mercedes]

OH! So that's what that was! I had a wobble the first time I took the Blast on an Interstate. I think I was going maybe 80 mph, hit a bump that was followed by a dip on a smooth curve, then suddenly I found my hips shaking like I was in a Shakira music video. :O Backed down on the throttle and it was all over in a second.