Tank slapper advice

kyle · Post by **kyle** » Sat Jul 28, 2007 6:35 pm

I've experienced a few of these, one very bad one during a run over the Carin o Mount which almost ended in disaster.

Can tank slappers only be reduced with the use of a steering dampener? or are there other measures that can be taken i.e suspension, tyres etc.

I'm starting to lose faith in the bike a little, because the shaking starts almost instantaneously without warning.

Your thoughts would be appreciated!

Regards

Hagar · Post by **Hagar** » Sat Jul 28, 2007 7:47 pm

kyle wrote:I've experienced a few of these, one very bad one during a run over the Carin o Mount which almost ended in disaster.

Can tank slappers only be reduced with the use of a steering dampener? or are there other measures that can be taken i.e suspension, tyres etc.

I'm starting to lose faith in the bike a little, because the shaking starts almost instantaneously without warning.

Your thoughts would be appreciated!

Regards

I am by no means an expert, but I seem to remember that this was talked about recently on here. The thought was that to stop a tank slapper you had to relax your grip on the bars and accelerate

I have had a quick look but I cannot find the last thread that discussed this; perhaps others will have a better idea were it is hidden.

coullstar · Post by **coullstar** » Sat Jul 28, 2007 8:12 pm

Not a lot you can do really. Going by your sig you have a new YZFR6 and with the geometry on that bike it will be prone to inducing tankslappers over bumps. The cairn road is crap and you would probably get a some wobble from a Harley on it as well.

I think the theory is as Hagar said but in reality you will just tense up and poo yourself. If your worried get a steering damper but get an adjustable one i.e. Scott, GPR or Ohlins.

The movement is probably not as much as you think it is. I personally dont mind it too much as it keeps you on your toes.

dedpidgin2 · Post by **dedpidgin2** » Sun Jul 29, 2007 1:10 am

I got a steering damper on my ZX after a socket-wrenching slapper on the Logie Coldstone - Dinnet road (everyone knows the corner!) - I specifically went back to that same corner and played with the damper on it... it made a huge difference. I'm sure that on a nice smooth track it's probably unnecessary with correct suspension settings, etc, and even on the road if you're taking it easy. But considering the vagaries of public road surfaces and stuff... I would recommend giving a damper a try.

cbr1100 · Post by **cbr1100** » Sun Jul 29, 2007 11:29 am

Relax on the bars, let it do its thing, keep it nailed, works for me..... :I can't believe it's not butter!

Post by **Zax** » Sun Jul 29, 2007 11:54 am

I fitted a damper to my YZFR6 after suffering 2 belting tank slappers.
1 at the infamous "logi Coldsone corner" and one on the way from Glenshee to Braemar. both these were years ago after fitting the damper not even a twitch of the bars even on the bumpiest of roads.

Dampers get the

from me.

fido · Post by **fido** » Sun Jul 29, 2007 12:23 pm

I do the opposite, try to pull both bars toward me. In effect this is doing the same action as the steering damper so appears to be the logical approach. This only applies to high speed tankslappers when going in a straight line as I've not had them in other circumstances. You should check wheel bearings, fork bushes, steering head bearings, tyre pressures, front wheel balance etc.

IZINBARD · Post by **IZINBARD** » Sun Jul 29, 2007 1:01 pm

Hee hee fido if you tried that on the "logi Coldsone corner" then you would end up being called Stumpy due to your arms being ripped right out of the shoulder sockets, very nasty bit of road that. Not had a straight line one so can't comment

fido · Post by **fido** » Sun Jul 29, 2007 2:15 pm

Yes, no doubt it's much more scary on a bend. I used to get them on my Kwak GT750 at about 90. It was true that you could accelerate out of them but then you had the prospect of it starting again when you slowed down to 90. I could have played about with air damping pressures and stuff but could not be arsed so I just kept it below 90 :I can't believe it's not butter!

Coddy · Post by **Coddy** » Sun Jul 29, 2007 2:27 pm

I had the demo YZFR6 from Ecosse for the day about 3 months back and had it shaking the bars, but not really a full blown tank slapper. I havent noticed the GSXR6 doing it (standard unadjustable dampner fitted) or cbr6 that i have had a few shotties of doing it.
If i was you, i would look at getting one fitted. I have and Ohlins one on my R1 and had an Ohlins one on a Mille Factory i owned and havent had any head shaking moments with them.

A dampner only works when you get a real tank slapper by restricting the speed at which the oil can flow through the dampner, and will not effect the normal steering on your bike (making it feel stiffer). If it does then the dampner is adjusted to high.

If you stay near Crichie(ish) a good road for you to try it out on after you fit one is from Mintlaw to Pitsliga. Excellent series of bend to get it set up, and you will know the road well.

If you do get another full lock to lock slapper, remeber to pump the brakes a few times as a big one can push the brake pistons back into the calipers. I for one certainly wouldnt pull on the bars as hard as possible as is stated above, each have their own method. The bike would shake your whole upper body, if your elbows are bent and relaxed your arms will take most of the wobble acting like shock absorbers for your upper body. The common concensus is to accelerate, which is all very well when you are close to shitting yourself

and trying to grip the seat with your ringpiece at the same time :I can't believe it's not butter! . I know i shut the throttle which is suposed to be bad.

As you have an YZFR6, go see Andy at Ecosse, he may have an Ohlins one in stock with the fitting kit if required.

kyle · Post by **kyle** » Sun Jul 29, 2007 3:55 pm

Coddy wrote:I had the demo YZFR6 from Ecosse for the day about 3 months back and had it shaking the bars, but not really a full blown tank slapper. I havent noticed the GSXR6 doing it (standard unadjustable dampner fitted) or cbr6 that i have had a few shotties of doing it.
If i was you, i would look at getting one fitted. I have and Ohlins one on my R1 and had an Ohlins one on a Mille Factory i owned and havent had any head shaking moments with them.

A dampner only works when you get a real tank slapper by restricting the speed at which the oil can flow through the dampner, and will not effect the normal steering on your bike (making it feel stiffer). If it does then the dampner is adjusted to high.

If you stay near Crichie(ish) a good road for you to try it out on after you fit one is from Mintlaw to Pitsliga. Excellent series of bend to get it set up, and you will know the road well.

If you do get another full lock to lock slapper, remeber to pump the brakes a few times as a big one can push the brake pistons back into the calipers. I for one certainly wouldnt pull on the bars as hard as possible as is stated above, each have their own method. The bike would shake your whole upper body, if your elbows are bent and relaxed your arms will take most of the wobble acting like shock absorbers for your upper body. The common concensus is to accelerate, which is all very well when you are close to shitting yourself and trying to grip the seat with your ringpiece at the same time :I can't believe it's not butter! . I know i shut the throttle which is suposed to be bad.

As you have an YZFR6, go see Andy at Ecosse, he may have an Ohlins one in stock with the fitting kit if required.

Thanks for the advice. Cats eyes tend to be a bit of an instigator also, maybe avoiding them is way of reducing the chances, however - easier said than done! I'll pop in past Ecosse to see what they can offer, the bike was bought from there anyway.

And re the Pitsligo road - it gets a thumbs up from me, many a slider has touched the tarmac on those corners!

Thanks Again.

Regards.

DarrenR · Post by **DarrenR** » Sun Jul 29, 2007 5:23 pm

my new zx6r was quite bad for giving you a bit of a shake but i had a matris dampner fitted thats adjustable and everythings fine now

my old YZFR6 was bad for them tho, overtaking cars and hitting a cats eye usually brought one on which was never really pleasant :I can't believe it's not butter!

CBRXX · Post by **CBRXX** » Mon Jul 30, 2007 9:23 am

Raised the back of my blackbird to get it turning quicker and it started shaking the bars for the first time so I turned up the damper 3 clicks but turned it back down 2 again after it stiffened the steering too much

jobs a good un and only gets a twitch when lifting the front wheel now

Backs 400 · Post by **Backs 400** » Mon Jul 30, 2007 11:02 am

Big difference between a shake of the head that you can indeed accelerate out of, and a full blown tank slapper which I believe no one, not even Rossi, could accelerate out of.

A steering damper will help but i would also check your suspension settings (supprised none of you gurus out there mentioned this!) Having the back pumped up hard and high (

) will have the effect of steepening the angles at the front and thus making head shakes more likely.

dale123 · Post by **dale123** » Tue Jul 31, 2007 7:22 am

For me at least, tankslappers happen when the front is light, such as on acceleration, and then a surface change, bumps, ripple, crossed up wheelie or cats eye set a weave off from the front, causing it to skip along.

By continuing to accelerate (or ignoring it) your taking the weight off and they settle down fairly quick. Chopping the throttle puts more weight on and this exaggerates the initial shake, sometimes into an out of control full on slapper, which you can only hang onto and see what happens.

A damper will generally slow down headshake and stop a bit of slap from turning into a smack in the face, and thats why everyone uses them. Hanging tight onto the bars generally puts the energy generated fom the front, back through the bike, and thats why were told not to have a light grip on the bike at any time.

Id fit a damper.

CBRXX · Post by **CBRXX** » Tue Jul 31, 2007 9:10 am

Backs 400 wrote:
A steering damper will help but i would also check your suspension settings (supprised none of you gurus out there mentioned this!) Having the back pumped up hard and high ( ) will have the effect of steepening the angles at the front and thus making head shakes more likely.

Ahem when I was talking about raising the back of my bike to quicken the turn in I wasn't talking about levitation or stoppies :I can't believe it's not butter!

shortassrider · Post by **shortassrider** » Tue Jul 31, 2007 5:55 pm

Are dampers universal ?

CBRXX · Post by **CBRXX** » Tue Jul 31, 2007 11:19 pm

shortassrider wrote:Are dampers universal ?

fraid not they can be different lengths dependant on where fitted and the amount of travel required due to the fitting brackets specific to the bike
although I reckon you could make one work on just about any bike, when I stripped the BB down I realized just how complicated it would have been to design the one that was fitted. as space was v tight and to prevent the damper itself fouling the clocks, inner fairing and bars lock to lock must have taken some time working out

Backs 400 · Post by **Backs 400** » Wed Aug 01, 2007 8:28 am

My wee ZXR had all the mounts in place, ready to go..just bolt on the appropriate Ohlins and away you went.

teamemmenracing · Post by **teamemmenracing** » Sat Feb 02, 2008 4:09 am

Just reading Dales reply ...... made me smile ....

YZFR6 ..... fit a steering damper period. Spend the money on a quality piece of kit. YZFR6 is a nice ride and really well balanced but it doesn't take much to set it off.
Mine have 14 clicks of adjustment, most tracks I go with 7 .... Knockhill its 11 ....

Its all about heat geometry ..... ZX7R I had ..... raised the rear by 1/2 inch and it went slap happy, changed to 1/4" was as stable a they come.

not2fast · Post by **not2fast** » Sat Feb 02, 2008 10:00 am

The very thing that allow's race rep bikes to change direction so quickly is low weight and a steep fork rake (small trail) but the trade off is the handling nervousness.
A steering damper is a elastoplast fix that will consequently affect the rate of lean change at the extremes of riding but it almost a guaranteed fix to stop the wobble.
Make sure that the tyres are an appropriate matched set in good order (again, race profile rubber helps the bike change direction quicker at the expense of stability) and also ensure that you have systematically gone through the suspension settings available.
Ensure that head and swingarm bearings are not worn as this does not help.
Tank slappers are usual the consequence of the riders body mass transferring energy from handle bar movement further back into the bike, causing the bike to try and correct this, causing the rider to brace himself on the bars forcing the direction change in the other direction and so it goes on. When going round bends quickly, try bracing your body onto the bike with your legs and don't grip the bars tight. Check your self to keep your elbows bent with forearms horizontal and not locked This will let the bike, tyres and suspension work as designed and will hopefully help.
You could of course also just slow down round corners a little

garymitch · Post by **garymitch** » Sat Feb 02, 2008 10:19 am

steering dampers all the way. i fitted a sprint one to a 1200 bandit i had and it stoped all head shaking.

dale123 · Post by **dale123** » Sat Feb 02, 2008 1:17 pm

teamemmenracing wrote:Just reading Dales reply ...... made me smile ....

You took your time doing it though John! :I can't believe it's not butter!

Dampers (most anyway) are adjustable so you can get the best balance between control and turn in.

Post by al » Sat Feb 02, 2008 3:31 pm

dedpidgin2 wrote:Logie Coldstone - Dinnet road (everyone knows the corner!)

I still don't have a bloody clue where this corner is! Someone is going to have to point it out to me some time.

As long as everything is in perfect nick on your bike I generally view a wee bit of flap a sign that I am pushing it and could do with backing off a bit. Having said that I very rarely push it so I've not expereinced them very often and even then it was mostly when exiting roundabouts.

Big Kneed Al (master of the emergency stop & "stand up" comedian).

dedpidgin2 · Post by **dedpidgin2** » Sat Feb 02, 2008 3:52 pm

Big Kneed Al (master of the emergency stop & "stand up" comedian) ( Super Nanny ) wrote:I still don't have a bloody clue where this corner is! Someone is going to have to point it out to me some time.

It's just North of Logie Codstone, rather than on the Dinnet side... my mistake.

http://maps.google.co.uk/maps?q=A97+%40 ... GB256GB256 if I remember correctly.

AberdeenBikers

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