What causes a tank slapper?
05-18-2008, 02:14 PM
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Re: What causes a tank slapper? (knockout)
indeed.
but i think one of the main causes is when your at speed, the wheel is for whatever reason jerked one way or the other, casusing the bike to shift rapidly, then you know the rest.
like if your changing lanes on a highway and theres an uneven road surface, like a 1" ridge may cause somthing like that.
another thing, is if your doing a wheelie and your front wheel doesnt come down dead straight.
in my short experience of riding its never happened to me, but i hear if you just roll off the throttle a little, that should really help. other cases ive heard you should roll a little on the throttle, so at this point im gonna have to ask someone with a little more experience to chime in.
but i think one of the main causes is when your at speed, the wheel is for whatever reason jerked one way or the other, casusing the bike to shift rapidly, then you know the rest.
like if your changing lanes on a highway and theres an uneven road surface, like a 1" ridge may cause somthing like that.
another thing, is if your doing a wheelie and your front wheel doesnt come down dead straight.
in my short experience of riding its never happened to me, but i hear if you just roll off the throttle a little, that should really help. other cases ive heard you should roll a little on the throttle, so at this point im gonna have to ask someone with a little more experience to chime in.
05-18-2008, 02:22 PM
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Re: What causes a tank slapper? (Blahblah718293)
"A tank-slapper (wild and rapid swings of the handlebars from hard-stop right to hard-stop left and back again) happens when harmonic feedback is generated following your front tire hitting an imperfection on the road surface such as the slight bump at the end of your driveway.
It usually happens at speeds of around 20 MPH - sometimes a little faster, sometimes a little slower - but it CAN happen at any speed!
I have heard otherwise well informed riders give advice to newbies about how to handle a tank-slapper. Usually it goes something like this: 'Just hit the throttle and lift the front-end off the ground. That will stop the oscillation."
Please! That advise is virtually assured of getting you into serious trouble - more than you were in when the tank-slapper began.
Harmonic feedback means that a small force is being applied EXACTLY in-phase with the end of a counter-force (shock absorber) which results in another 'bounce' of the system AND AN AMPLIFICATION of the previous bounce.
The second time it happens the amplification is huge. The third time and you eat asphalt - maybe the fourth time...
It is exactly the same principal that keeps your old grandfather's clock pendulum swinging - it gets a tiny 'kick' at exactly the right time (in-phase) at the end of each swing.)
Your bike probably has one of two kinds of devices in it designed to prevent these from happening:
-A small shock absorber attached to the steering stem
-A pressure bearing within the triple-tree
These are called steering head dampers or 'stabilizers'. Their sole legitimate purpose is to disrupt harmonic feedback and, thus, stop tank-slappers before they start. Some vendors (and motorcycle shops) will tell you to get one in order to stop your front-end from 'shaking'. NUTS! If your front-end shakes at any speed there is something wrong with the suspension.
If your steering head damper is weak or maladjusted then it cannot dampen (and, thus, kill harmonic feedback) shocks to the front-end.
As to suggestions about how to handle one if it happens... it is NEVER appropriate or safe to do a wheelie. Your response should be to hold firmly to both grips and absorb the 'harmonic feedback' into your arms, dampen the handlebars - and grabbing a handful of the front brake. Then go get it fixed!
Your NUMBER ONE RESPONSIBILITY on a bike is to maintain control of it.
For those giving advice... if your bike is already out of control do you really think it makes sense to increase speed? To do a wheelie? Does it not occur to you that you were traveling at some rate of speed and it was just a minor imperfection in the road surface that started this and that when you come back down from a wheelie, going faster than you were, that front-end is going to get a severe jolt? What do you think the odds are of going into another tank-slapper then?
You must disrupt the harmonic. You do that by stiffening your arms and changing the front-end geometry, if you can. Braking, by the way, both slows you down so that if you do hit the ground it won't hurt as much, and it compresses the front shocks which changes the front-end geometry.
Sound like a better alternative to you than hitting the after-burner?"
EDIT: All cited directly from http://www.msgroup.org/tip.aspx?num=190
So to answer your question, if you have not already seen it, tanks slapper are caused by harmonics from a sudden jolt applied to your front end from imperfections in the road.
Modified by DirtySol at 9:46 PM 5/18/2008
It usually happens at speeds of around 20 MPH - sometimes a little faster, sometimes a little slower - but it CAN happen at any speed!
I have heard otherwise well informed riders give advice to newbies about how to handle a tank-slapper. Usually it goes something like this: 'Just hit the throttle and lift the front-end off the ground. That will stop the oscillation."
Please! That advise is virtually assured of getting you into serious trouble - more than you were in when the tank-slapper began.
Harmonic feedback means that a small force is being applied EXACTLY in-phase with the end of a counter-force (shock absorber) which results in another 'bounce' of the system AND AN AMPLIFICATION of the previous bounce.
The second time it happens the amplification is huge. The third time and you eat asphalt - maybe the fourth time...
It is exactly the same principal that keeps your old grandfather's clock pendulum swinging - it gets a tiny 'kick' at exactly the right time (in-phase) at the end of each swing.)
Your bike probably has one of two kinds of devices in it designed to prevent these from happening:
-A small shock absorber attached to the steering stem
-A pressure bearing within the triple-tree
These are called steering head dampers or 'stabilizers'. Their sole legitimate purpose is to disrupt harmonic feedback and, thus, stop tank-slappers before they start. Some vendors (and motorcycle shops) will tell you to get one in order to stop your front-end from 'shaking'. NUTS! If your front-end shakes at any speed there is something wrong with the suspension.
If your steering head damper is weak or maladjusted then it cannot dampen (and, thus, kill harmonic feedback) shocks to the front-end.
As to suggestions about how to handle one if it happens... it is NEVER appropriate or safe to do a wheelie. Your response should be to hold firmly to both grips and absorb the 'harmonic feedback' into your arms, dampen the handlebars - and grabbing a handful of the front brake. Then go get it fixed!
Your NUMBER ONE RESPONSIBILITY on a bike is to maintain control of it.
For those giving advice... if your bike is already out of control do you really think it makes sense to increase speed? To do a wheelie? Does it not occur to you that you were traveling at some rate of speed and it was just a minor imperfection in the road surface that started this and that when you come back down from a wheelie, going faster than you were, that front-end is going to get a severe jolt? What do you think the odds are of going into another tank-slapper then?
You must disrupt the harmonic. You do that by stiffening your arms and changing the front-end geometry, if you can. Braking, by the way, both slows you down so that if you do hit the ground it won't hurt as much, and it compresses the front shocks which changes the front-end geometry.
Sound like a better alternative to you than hitting the after-burner?"
EDIT: All cited directly from http://www.msgroup.org/tip.aspx?num=190
So to answer your question, if you have not already seen it, tanks slapper are caused by harmonics from a sudden jolt applied to your front end from imperfections in the road.
Modified by DirtySol at 9:46 PM 5/18/2008
05-18-2008, 02:28 PM
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Re: What causes a tank slapper? (DirtySol)
05-18-2008, 02:59 PM
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Re: What causes a tank slapper? (DirtySol)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DirtySol »</TD></TR><TR><TD CLASS="quote">here is a movie that I found:
http://www.msgroup.org/images/tankslapper.asx</TD></TR></TABLE> from what i remember about seeing that vid before, i think a suspension component broke on his bike and caused that slapper. most def scary.
http://www.msgroup.org/images/tankslapper.asx</TD></TR></TABLE> from what i remember about seeing that vid before, i think a suspension component broke on his bike and caused that slapper. most def scary.
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05-18-2008, 04:05 PM
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Re: What causes a tank slapper? (egryda)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DirtySol »</TD></TR><TR><TD CLASS="quote">here is a movie that I found:
http://www.msgroup.org/images/tankslapper.asx</TD></TR></TABLE>
Wow... it seems the guy held on long enough to maybe let the bike slow down just a tad. Scary ****
http://www.msgroup.org/images/tankslapper.asx</TD></TR></TABLE>
Wow... it seems the guy held on long enough to maybe let the bike slow down just a tad. Scary ****
05-18-2008, 05:20 PM
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Re: What causes a tank slapper? (95ProjectEJ1)
OK - I haven't posted in ages, but the advice here is wrong.
If you stiff arm the bars, try and make your arms dampers, you're going to become an amplifying part of the oscillation. Amplify the osciallation, and you're going off the high side. Don't do it. Loosen your grip.
If you roll off, and/or grab the brakes, you're going to load the front tire while it's not in line with the motorcycle's direction of travel. When you do that, the front's going to wash and you'll end up on the ground.
I don't know what this stuff about "20mph" is... but it's not accurate, or relevant. It's also a little misleading. If you somehow manage to slap at 20, you could probably pretty easily clamp the binder and have no ill effects. And that would teach you that it is the appropriate response. Try it as 70, 80, 100+, and see what happens (note: answer above).
Speaking from experience, and the physics does agree: roll on the gas. Don't clutch up a wheelie, just roll on the gas and ride it out. Doing this unweights the front wheel and removes half of the oscillatory agent.
A tankslapper is not perpetuated by the rear shock. It's a function of gyroscopic precession: the front wheel is bumped while not in line with the track of the motorcycle in such a fashion that the forks don't absord the impact - the wheel gets knocked out of line and the wheel's gyroscopic precession pushes back. The push back causes the same reaction the other direction, and as the bike's mass becomes increasingly involved, the situation is amplified until you end up like the guy in the video.
If slowing down DID stop a slapper, then that guy's would have naturally sorted... he was slowing down the entire time he was out of control.
If you stiff arm the bars, try and make your arms dampers, you're going to become an amplifying part of the oscillation. Amplify the osciallation, and you're going off the high side. Don't do it. Loosen your grip.
If you roll off, and/or grab the brakes, you're going to load the front tire while it's not in line with the motorcycle's direction of travel. When you do that, the front's going to wash and you'll end up on the ground.
I don't know what this stuff about "20mph" is... but it's not accurate, or relevant. It's also a little misleading. If you somehow manage to slap at 20, you could probably pretty easily clamp the binder and have no ill effects. And that would teach you that it is the appropriate response. Try it as 70, 80, 100+, and see what happens (note: answer above).
Speaking from experience, and the physics does agree: roll on the gas. Don't clutch up a wheelie, just roll on the gas and ride it out. Doing this unweights the front wheel and removes half of the oscillatory agent.
A tankslapper is not perpetuated by the rear shock. It's a function of gyroscopic precession: the front wheel is bumped while not in line with the track of the motorcycle in such a fashion that the forks don't absord the impact - the wheel gets knocked out of line and the wheel's gyroscopic precession pushes back. The push back causes the same reaction the other direction, and as the bike's mass becomes increasingly involved, the situation is amplified until you end up like the guy in the video.
If slowing down DID stop a slapper, then that guy's would have naturally sorted... he was slowing down the entire time he was out of control.
05-18-2008, 05:45 PM
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Re: What causes a tank slapper? (ASteele2)
I did not write that, it came directly from Motorcycle Safety page, as did the video......I should have noted that.
I have been lucky enough to have never encountered a TS.
Let me find the link.......
I have been lucky enough to have never encountered a TS.
Let me find the link.......
05-18-2008, 05:47 PM
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Re: What causes a tank slapper? (DirtySol)
here you go, Motorcycle Safety: Tips & Techniques...... http://www.msgroup.org/tip.aspx?num=190
05-18-2008, 06:04 PM
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Re: What causes a tank slapper? (ASteele2)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ASteele2 »</TD></TR><TR><TD CLASS="quote">You found it on the internets, so it must be true?
I don't care where you found it, it's wrong.</TD></TR></TABLE>
duely noted
maybe I will send them an email or something
I don't care where you found it, it's wrong.</TD></TR></TABLE>
duely noted
maybe I will send them an email or something
05-18-2008, 07:41 PM
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Re: What causes a tank slapper? (ASteele2)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ASteele2 »</TD></TR><TR><TD CLASS="quote">OK - I haven't posted in ages, but the advice here is wrong.
If you stiff arm the bars, try and make your arms dampers, you're going to become an amplifying part of the oscillation. Amplify the osciallation, and you're going off the high side. Don't do it. Loosen your grip.
If you roll off, and/or grab the brakes, you're going to load the front tire while it's not in line with the motorcycle's direction of travel. When you do that, the front's going to wash and you'll end up on the ground.
I don't know what this stuff about "20mph" is... but it's not accurate, or relevant. It's also a little misleading. If you somehow manage to slap at 20, you could probably pretty easily clamp the binder and have no ill effects. And that would teach you that it is the appropriate response. Try it as 70, 80, 100+, and see what happens (note: answer above).
Speaking from experience, and the physics does agree: roll on the gas. Don't clutch up a wheelie, just roll on the gas and ride it out. Doing this unweights the front wheel and removes half of the oscillatory agent.
A tankslapper is not perpetuated by the rear shock. It's a function of gyroscopic precession: the front wheel is bumped while not in line with the track of the motorcycle in such a fashion that the forks don't absord the impact - the wheel gets knocked out of line and the wheel's gyroscopic precession pushes back. The push back causes the same reaction the other direction, and as the bike's mass becomes increasingly involved, the situation is amplified until you end up like the guy in the video.
If slowing down DID stop a slapper, then that guy's would have naturally sorted... he was slowing down the entire time he was out of control.</TD></TR></TABLE>
I agree with rolling on the throttle, however I don't agree with loosening your grip. While I am still a newbie to motorcycles, I had a brief experience with minor ts. I braced my arms (not locking) and squeezed the tank with my legs. This was recommended to me by a buddies friend who has had his fair share of ts'ers. Low and behold I was able to come out of it.
What is your opinion on this?
If you stiff arm the bars, try and make your arms dampers, you're going to become an amplifying part of the oscillation. Amplify the osciallation, and you're going off the high side. Don't do it. Loosen your grip.
If you roll off, and/or grab the brakes, you're going to load the front tire while it's not in line with the motorcycle's direction of travel. When you do that, the front's going to wash and you'll end up on the ground.
I don't know what this stuff about "20mph" is... but it's not accurate, or relevant. It's also a little misleading. If you somehow manage to slap at 20, you could probably pretty easily clamp the binder and have no ill effects. And that would teach you that it is the appropriate response. Try it as 70, 80, 100+, and see what happens (note: answer above).
Speaking from experience, and the physics does agree: roll on the gas. Don't clutch up a wheelie, just roll on the gas and ride it out. Doing this unweights the front wheel and removes half of the oscillatory agent.
A tankslapper is not perpetuated by the rear shock. It's a function of gyroscopic precession: the front wheel is bumped while not in line with the track of the motorcycle in such a fashion that the forks don't absord the impact - the wheel gets knocked out of line and the wheel's gyroscopic precession pushes back. The push back causes the same reaction the other direction, and as the bike's mass becomes increasingly involved, the situation is amplified until you end up like the guy in the video.
If slowing down DID stop a slapper, then that guy's would have naturally sorted... he was slowing down the entire time he was out of control.</TD></TR></TABLE>
I agree with rolling on the throttle, however I don't agree with loosening your grip. While I am still a newbie to motorcycles, I had a brief experience with minor ts. I braced my arms (not locking) and squeezed the tank with my legs. This was recommended to me by a buddies friend who has had his fair share of ts'ers. Low and behold I was able to come out of it.
What is your opinion on this?
05-18-2008, 08:00 PM
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Re: What causes a tank slapper? (tegmech)
I have suffered a couple tankslappers...thankfully in part to the beautiful asphalt we have in here. Both of them have been aprox at 70-80 MPH.
I kept a loose grip on the bars, and proceeded to give a little more throttle. But it happens so fast, that you can barely react. I think luck plays a great part on recovering from a TS, more so a serious one (Mine I guess could been described as a moderate headshake?).
I kept a loose grip on the bars, and proceeded to give a little more throttle. But it happens so fast, that you can barely react. I think luck plays a great part on recovering from a TS, more so a serious one (Mine I guess could been described as a moderate headshake?).
05-18-2008, 08:06 PM
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Re: What causes a tank slapper? (ASteele2)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ASteele2 »</TD></TR><TR><TD CLASS="quote">OK - I haven't posted in ages, but the advice here is wrong.
If you stiff arm the bars, try and make your arms dampers, you're going to become an amplifying part of the oscillation. Amplify the osciallation, and you're going off the high side. Don't do it. Loosen your grip.
.</TD></TR></TABLE>
have had a ts happen twice. both at about 80-105 mph.. once, i was getting on the freeway, hit a pavement crack, bars slapped back and forth, luckily damper saved it that time, it just stopped after i loosend my grip..
second time, at the track, about 105 mph, front tire came off the ground, landed crooked, started slapping.. got on the gas, and it got worse,( thats what someone had told me to do, dont do it, it makes it worse.. or my 600 didnt have enough power to pull the front tire off the ground,lol.) i loosened my grip on the bars, and squeezed the tank with my legs, it just stopped all of the sudden..
bottom line, to stop it, geta damper.ther worth their weight in gold
.. /end
If you stiff arm the bars, try and make your arms dampers, you're going to become an amplifying part of the oscillation. Amplify the osciallation, and you're going off the high side. Don't do it. Loosen your grip.
.</TD></TR></TABLE>
have had a ts happen twice. both at about 80-105 mph.. once, i was getting on the freeway, hit a pavement crack, bars slapped back and forth, luckily damper saved it that time, it just stopped after i loosend my grip..
second time, at the track, about 105 mph, front tire came off the ground, landed crooked, started slapping.. got on the gas, and it got worse,( thats what someone had told me to do, dont do it, it makes it worse.. or my 600 didnt have enough power to pull the front tire off the ground,lol.) i loosened my grip on the bars, and squeezed the tank with my legs, it just stopped all of the sudden..
bottom line, to stop it, geta damper.ther worth their weight in gold
.. /end
05-18-2008, 10:10 PM
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Re: What causes a tank slapper? (ASteele2)
Ya I gotta say... You aint gonna hardly be able to do **** in a slapper. My 06 R6 loves to get into em, esp when im lite on fuel. And ive been in more than a few of them over the years, worst at about 80mph. Hang on! Try and relax but not too much! And hope for the best. LOL.. The notion that your gonna be able to wheelie from a slapper made me laugh. In a serious one youll be lucky if you can hold on, let alone add throttle, or pop into a wheelie.
DS, for as long as you have been riding you have never been in a TS? That smells a bit fishy... almost like calamari. JK
DS, for as long as you have been riding you have never been in a TS? That smells a bit fishy... almost like calamari. JK
05-19-2008, 12:16 AM
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Re: What causes a tank slapper? (pwr2lbs)
in my 10+ years of riding as a licensed rider, I have never had a runin with a TS. I have had a bit of head shake, but never anything as violent as a tank slapper. I try very hard to avoid such situations and if I have a bike with a steep head angle, I install a dampener before I even think of riding it, that is if it does not already have one.
The closest two times that I can think of is one time when I was learning to ride a wheelie, I came down too hard and wih the bars just a little crooked. It jerked about two times but I got it under control. The other time was coming down the road on the way to my current house on teh bike I currently ride. I made the turn and found a big bump in the road (which I now aviod) and it sent the bike airborne making the entire shake pretty bad, I was VERY VERY close to having a TS.
I have been lucky I guess, or just really careful. I try very hard to aviod potholes on the interstate, I approach shifts in the road at as an aggressive of an angle as possible so that the tire is not trying to climb up sideways.....there are a bunch of things that I try to do to aviod such a disiaster......I have had a lot of luck thus far. ::knock on wood::
The closest two times that I can think of is one time when I was learning to ride a wheelie, I came down too hard and wih the bars just a little crooked. It jerked about two times but I got it under control. The other time was coming down the road on the way to my current house on teh bike I currently ride. I made the turn and found a big bump in the road (which I now aviod) and it sent the bike airborne making the entire shake pretty bad, I was VERY VERY close to having a TS.
I have been lucky I guess, or just really careful. I try very hard to aviod potholes on the interstate, I approach shifts in the road at as an aggressive of an angle as possible so that the tire is not trying to climb up sideways.....there are a bunch of things that I try to do to aviod such a disiaster......I have had a lot of luck thus far. ::knock on wood::
05-19-2008, 04:00 AM
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Re: What causes a tank slapper? (4LugR)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 4LugR »</TD></TR><TR><TD CLASS="quote">it just stopped after i loosend my grip... i loosened my grip on the bars, and squeezed the tank with my legs, it just stopped all of the sudden..
bottom line, to stop it, geta damper.ther worth their weight in gold .. /end</TD></TR></TABLE>
Sounds like the damper isnt fixing the issue...
bottom line, to stop it, geta damper.ther worth their weight in gold
.. /end</TD></TR></TABLE>Sounds like the damper isnt fixing the issue...
05-19-2008, 04:19 AM
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Re: What causes a tank slapper? (.RJ)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by .RJ »</TD></TR><TR><TD CLASS="quote">
Sounds like the damper isnt fixing the issue... </TD></TR></TABLE>
+1
Also: wobbles aren't slappers. Just because things got a little hairy and the bars moved a little bit doesn't mean you were in a slapper.
Sounds like the damper isnt fixing the issue... </TD></TR></TABLE>
+1
Also: wobbles aren't slappers. Just because things got a little hairy and the bars moved a little bit doesn't mean you were in a slapper.
05-19-2008, 10:15 AM
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Re: What causes a tank slapper? (DirtySol)
Well your not missing out on anything! Hahaha Had a 45mph slapper rip both feet off of the pegs.. good times. Washington rain makes for some real crappy roads! A regular pot hole heaven.
05-19-2008, 10:36 AM
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Re: What causes a tank slapper? (pwr2lbs)
I'll comment since I recently survived a horrid tank slapper that felt like that video looks. My buddy that was behind me said it looked like that.
I've had a couple little head shakes on my SV before. Usually when exiting a corner on a bumpy road, but nothing that ever felt out of my control. I'm loose on the bars all the time, and every time I got a little head shake I just continued on as normal and it was fine.
But, three weeks ago I was riding with my friend, heading back to our house, and there's this 1 mile long straight stretch that goes down this big valley and back up. There's a small 'hump' about in the bottom of the valley where the altitude comes back up again and the road is fairly crappy (read: bumpy).
We were stuck behind a car going slow until just before the middle when they pulled off into one of the two driveways. I was leading, so I hammered down in first gear and the little SV took off.
I was in third or fourth gear about to crest the little 'hump' in the middle so I let off the throttle to put wait back on the front end as I crested, and once I started coming down the backside I got back on the throttle.
All of a sudden the bars started whipping back and forth, almost full lock. I knew right away this wasn't one of the little head shakes I get. I remember remaining calm and not really thinking of anything to do, but I remember after a second or so I thought "****, i'm not wearing my 2-piece, and this is really gonna suck..."
Then, it just stopped and I tried to roll on the throttle to go up the hill but noticed I wasn't getting any power. This is because the bars actually knocked at least my right hand loose and it slapped the kill switch, and sprained my thumb.
So in my situation it seems that deceleration may have played a part. I've heard everyone say just about everything on how to qwell a tank slapper, and frankly I don't know which one to trust. And obviously it didn't matter because it all happened so fast I didn't know what to do.
I've had a couple little head shakes on my SV before. Usually when exiting a corner on a bumpy road, but nothing that ever felt out of my control. I'm loose on the bars all the time, and every time I got a little head shake I just continued on as normal and it was fine.
But, three weeks ago I was riding with my friend, heading back to our house, and there's this 1 mile long straight stretch that goes down this big valley and back up. There's a small 'hump' about in the bottom of the valley where the altitude comes back up again and the road is fairly crappy (read: bumpy).
We were stuck behind a car going slow until just before the middle when they pulled off into one of the two driveways. I was leading, so I hammered down in first gear and the little SV took off.
I was in third or fourth gear about to crest the little 'hump' in the middle so I let off the throttle to put wait back on the front end as I crested, and once I started coming down the backside I got back on the throttle.
All of a sudden the bars started whipping back and forth, almost full lock. I knew right away this wasn't one of the little head shakes I get. I remember remaining calm and not really thinking of anything to do, but I remember after a second or so I thought "****, i'm not wearing my 2-piece, and this is really gonna suck..."
Then, it just stopped and I tried to roll on the throttle to go up the hill but noticed I wasn't getting any power. This is because the bars actually knocked at least my right hand loose and it slapped the kill switch, and sprained my thumb.
So in my situation it seems that deceleration may have played a part. I've heard everyone say just about everything on how to qwell a tank slapper, and frankly I don't know which one to trust. And obviously it didn't matter because it all happened so fast I didn't know what to do.
05-19-2008, 11:41 AM
#24
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Re: What causes a tank slapper? ()
I've had 4 tanks slappers all at 100 mph or so coming down the end of the 1/8th mile track...after i crossed the beams and let off the throttle (closed the throttle too quickly)...obviously since you have minimal stopping distance before you run off the end of the track acceleration is not possible.
What all of the guys that i've raced with have told me is to keep a relaxed grip on the handlebars, and pick your butt up off the seat a little bit, maybe 1-2 inches...
Did that all 4 times and never had a problem getting on the brakes after the tank slapper quit. (i'm not talking headshake either...slappers.)
Works for me...i think it depends on the situation in which the tank slapper occured...just feel the bike out.
What all of the guys that i've raced with have told me is to keep a relaxed grip on the handlebars, and pick your butt up off the seat a little bit, maybe 1-2 inches...
Did that all 4 times and never had a problem getting on the brakes after the tank slapper quit. (i'm not talking headshake either...slappers.)
Works for me...i think it depends on the situation in which the tank slapper occured...just feel the bike out.
05-19-2008, 11:43 AM
#25
My Name is Nobody
Re: What causes a tank slapper? (rdblckSV650S)
there certainly is no easy answer to this phenomenon... there will be times when you need to roll off the throttle to alleviate the issue, and there will be times when you need to apply gentle acceleration... the trick is FEELING what the bike is doing and being instantaneously actionable to reconcile the issue. I think nine times out of ten the bike will correct itself when you gently and naturally roll off the throttle, the human tendency is to "lift" when you feel something weird and because of the gyroscopic effect of the un-sprung weight, the bikes will most always want to straighten up and track along the line/direction it is pointing. One thing is for certain, DO NOT LOCK YOUR ARMS and try to fight the harmonics... you are going to loose that battle every time. You need to loosen up and maintain control, unnaturally letting the bike do what it wants until the undulations start to subside... and like I said, at times adding a little throttle helps soften the undulations and sometimes lifting helps. 