tank slappers

beerock · 05-16-2008, 1:14 PM

was curious if this occurs on the rc51?

I know yamahas are notorious for it

cbr900091177 · 05-16-2008, 4:45 PM

not had a rc51 but i think it could happen on most sports bikes, i had a bad one on my nsr 250 and recently a minor one on my cbr900 but never on my cbr600

Ol' Gravy Leg · 05-16-2008, 5:07 PM

probability of a tank slapper is inversely proportional to the bike's trail. the more trail; the less shake.

the rc-51 has a trail of ~95mm. this is pretty aggresive for a motorcycle, but average for a sport bike.

cbr900091177 · 05-16-2008, 5:14 PM

Quote:

Originally Posted by Ol' Gravy Leg

probability of a tank slapper is inversely proportional to the bike's trail. the more trail; the less shake.

the rc-51 has a trail of ~95mm. this is pretty aggresive for a motorcycle, but average for a sport bike.

hi OGL could you put that in laymans terms ,thanks.

rokitt51 · 05-16-2008, 5:47 PM

Quote:

Originally Posted by beerock

was curious if this occurs on the rc51?

I know yamahas are notorious for it

Hell yeah it will occur on an RC, mine did it alot, under hard riding conditions. But the bike is very managable when it does happen. Al least i think so.

thatkindasux · 05-22-2008, 11:58 AM

yes RCs are known for tank slapping.
most people put a damp. on them.

if it starts to get shakey stay ON the throttle, the fastest way to come OFF the bike is rolling off the throttle.

Chum · 05-22-2008, 7:50 PM

I dont want to sound stupid or anything, but I'm not firmilar with the term, "tank slapper."
Can anyone fill me in?
Thanks, Chum

beerock · 05-22-2008, 10:14 PM

Quote:

Originally Posted by thatkindasux

yes RCs are known for tank slapping.
most people put a damp. on them.

if it starts to get shakey stay ON the throttle, the fastest way to come OFF the bike is rolling off the throttle.

I told the guys at dmv that the question on there exam is DEAD wrong and they could hurt a lot of people because of it. it says roll off the throttle. Ihad told them your suppose to get on the throttle

JasonR · 05-22-2008, 11:15 PM

chum......a tank slapper is when the front will shimmy on you and can get violent enough to throw you off. If a tank slapper starts as you accelerate and happens at a certain speed say 90 and you slow down to 85 it will stop. I have had this happen because of a worn out swing arm bushing in my old vintage bikes, but on the other hand if you come down from a wheelie and it goes into a tank slapper because you came down wrong you need to get on the throttle to make it come out of it. I hope that helps a little.

Jason

thatkindasux · 05-23-2008, 12:05 PM

tanks slapper: YouTube - Tank slapper Isle of Mann TT

say a first to second shift or second to third, fully on the throttle the front end is light or a little off the ground and touches back down with more weight on the front end than it had during accelaration. Its a quick oscillation between 4-10Hz @ the front end(wikipedia). A steering dampener will correct this problem, both rotory and piston.

rolling OFF the throttle will only induce more wobble and highside you fast! Stay on the throttle and power out, the front wheel is acting like a gyro and the more speed it develops the more rigitity in space it will have or something.

Chum · 05-23-2008, 2:47 PM

Thanks guys!. I dont have to worry about the wheelie thing, and wont be visiting 90mph too often, but will take your generous advice. Thanks again

KDA · 05-23-2008, 2:48 PM

Never had any headshake on mine. I ride track only and do not have a damper. Thought about getting one, but it's been dead on stable even powering over track curbing in switch-backs etc.

Motophoria · 05-23-2008, 11:03 PM

Even though the RC is fairly stable, I ran a Scott's damper on my SP2, and it came in handy it in certain situations, eg bumps, varioius throttle openings etc.

That said, I have the complete mounting kit for sale if anyone is looking for one, pm me.