Tank Slapper

[F6BANGER]

Has any one had or know of anyone that had a tank slapper on their Valkyrie? Today it almost felt like my bike was just thinking of having a fit. After about 1/4 second she smoothed out. 

[Daniel Meyer]

I've had one...on an xs11 at very high speed...but it had notoriously flexible frame and forks.

The valk should be smooth as glass under pretty much any loading or conditions. Given the abuse I dish out to mine, I cannot imagine the circumstances where a valk in good condition would do it.

Culprits if it seems to be heading that way:

Tires (front or back, either can be bad)
Swing arm bearings
Head bearings
Fork bushings/fluids

Most likely on the valk in my experience are bad tires, followed by bad head bearings.

[Stanley Steamer]

Has any one had or know of anyone that had a tank slapper on their Valkyrie? Today it almost felt like my bike was just thinking of having a fit. After about 1/4 second she smoothed out. 

I ALMOST had one a few yrs ago.....at 124mph on the GPS.....it was all I could do to keep the bars from slapping the tank....eased my butt off the seat and a little back brake to bleed the speed off and I came out of it....I had just passed a couple of Hardleys on a long downhill straightaway with a curve at the bottom....I was also loaded down weight wise coming back from a Memorial Day ride...

[Stanley Steamer]

I've had one...on an xs11 at very high speed...but it had notoriously flexible frame and forks.

The valk should be smooth as glass under pretty much any loading or conditions. Given the abuse I dish out to mine, I cannot imagine the circumstances where a valk in good condition would do it.

Culprits if it seems to be heading that way:

Tires (front or back, either can be bad)
Swing arm bearings
Head bearings
Fork bushings/fluids

Most likely on the valk in my experience are bad tires, followed by bad head bearings.

My front tire didn't have much tread left on it, BUT.....I feel like the front end got too light as the fairing took a LOT of wind under it...

[wizard -vrccds#125]

I did at 135 mph it was all I could do not to grab brake or make anyother sudden moves. Found out later the rear CT was not speed rated as I was told when I bought it ! Took me 30 min. to stop shaking.

[Walküre]

I did at 135 mph it was all I could do not to grab brake or make anyother sudden moves. Found out later the rear CT was not speed rated as I was told when I bought it ! Took me 30 min. to stop shaking.

Wiz - can you elaborate on which tire that was, and the circumstances? I'm pretty sure I'm going C/T next, but still doing research, and wondering if the tire was advertised wrongly, or an inept salesperson to blame...

Thx,

Roger

[Stanley Steamer]

I did at 135 mph it was all I could do not to grab brake or make anyother sudden moves. Found out later the rear CT was not speed rated as I was told when I bought it ! Took me 30 min. to stop shaking.

It never did bother me....I guess I was just too young and full of....something!!.....lol...

[wizard -vrccds#125]

Bad saleperson and shame on me for not checking it myself. Went back it Altamax again. My 4th one.

[therapist]

High performance, summer only tire is my advice re:CT. 

My Toyo Proxes T1-R is Speed rated -W (168 MPH). 

Never any tank slapping when I go fast...some shivers up my spine, but no slapping.  Well, I take that back.  My wife slaps the back of my helmet when I go too fast for her comfort 

[fudgie]

did it to me about 7 yrs ago. Can over a hill and a car was stopped. Laid on the brakes and left marks. Bars started slapping. Kept it up right with help of my massive muscular arms.  Only time tho. I'm guessing it was cause I had a MC tire on the back. 

[Jeff K]

I had it happen coming off an on ramp. I was going on to the hwy and cranked the throttle, the back tire broke loose and the bike went into a violent shake when I let off the throttle, So as half of my brain was preparing to crash, the other half of my brain remembered what the Metzler tire R&D rider told me. So I got back on the throttle gently and it straightened out. Joanne was behind me she saw it all happen. She was surprised I didn't stop to change shorts.

[EEEZZRIDER]

Almost lost my life two years ago as my baby went bonkers at 110. It was so violent that I could not even pull the brake lever for fear that that I would not be able hold on to the grip. I found out later later that I had taken on a nail in the front tire and it had only 24 pounds in it. Another reason to watch your air pressure !!!!!!!!!!!

[Romeo]

I thought I was going to experience one today. Had just passed a Hardley on the right. It was on a two lane that has passing lanes in certain areas. I was behind him , he was behind a car. As we entered the passing area, the car pulled to the right, the Hardley went past, with me on his tail. Instead of pulling into the right lane ahead of the car as he should have , this dipstick continues on in the passing lane, with me pushing him from behind. I finally lost patience with him and went around him in the right lane. As I pulled back into the left lane ahead of him to pass another vehicle, I was probably traveling 80-85,
when I crossed the seam between the two lanes, I felt the bike begin to wobble. I continued on as did the wobble until I reduced my speed to near 70mph. I have never felt her do that before. When we stopped I check air pressures and everything was fine. Very strange.

[Rowdy]

  Yep about 5 years ago on the way to work - going about 55 mph while stuck between 2 trucks  when this empty trash can was sucked accross the road by the truck in front of me, I tried to avoid the trash can but it kept coming and I was running out of realestate  .  I suspect I was in a bit of a lean trying to turn out of it's path and hit the brakes some - then it started - like someone had mentioned I was preparing for the crash when at the same time I was thinking if I survive the crash I have this big truck behind me tail gating me  not good - I finally got her back under control  and missed the trash can 

[Printer Mike]

Not long after I got my Valk last year, I made a rather brisk 125 mile run to get to my daughter who was about to have surgery.

Happened at around 110(gps). Later, found front tire air pressure a little low. No problem since.

[solo1]

Daniel gave some good reasons for tank slappers.  I can add another, changing the trail by redoing the triple tree for more rake.  It's ok on sidecar rigs as it makes the rig steer easier.  However, on two wheels it reduces the safety factor that Honda built into the Valkyrie.  If you add a parameter like a low front tire, you could be in trouble quickly.

Yes, I know that there are people out there that sell modified triple trees for two wheelers and say it's safe.  However, I didn't live this long by taking someone's word for safety.

Losing your life for the sake of "cool" looks is not a a good trade IMHO.


I just had to add a PS.  I consider this as an excellent thread. Every post here has absolutely good info for us.  It's so nice to see a productive and/or interesting  MOTORCYCLE thread ever once in awhile.  The same goes for trip threads with or without pics!

[Jabba]

On the Whisky Run.  100 MPH.  I got out of it pretty quick.  Scared me a little though.  On my IS. 

Remember, grab the tank with your legs... NO front brake.

Jabba

[fudgie]

On the Whisky Run.  100 MPH.  I got out of it pretty quick.  Scared me a little though.  On my IS. 

Remember, grab the tank with your legs... NO front brake.

Jabba

Dam, some prick musta been leading the pack. 

[Lyn-Del]

In Wizard's defense (about the shaking for 30 minutes) he had just been clipped by a car trying to pass him on the shoulder.  I'm thankful he had the leather bags on then, because I believe the bag absorbed much of the impact.  The tank slapper occurred when he tried to chase down the Mercedes to get the license number.

It took me a lot longer to stop shaking.  He shot past me in a hurry, and I had no idea what was happening.  When the bike started slapping around, I thought I was going to have a heart attack right there on the freeway. 

The tire was purchased at Discount Tire, I don't remember which it was, but it was a brand that was well recommended here on the board.  We've since settled on the Altimax.