Head shake/Tank Slap on deceleration

I have had this same problem for a couple months. I had my steering head tension checked... good as new. Then I had my steering stabilizer checked... it was not completely full. There was plenty enough air in the stabilizer to allow this to happen. Funny thing is that there was absolutley no sign of leakage. So, I had them service the stabilizer with 15W oil and double check for leaks. Its good to go now...
 
Check tires, steering dampner, bearings any of those thing could cause your problem.
 
My 08 has always been rock solid....I could come to a stop with my hands off the bars ( I know keep your freakin hands on the bars:whistle:) I just had a new set of BTO16's installed and I now have a slight shimmy which is very annoying. I took my wheel/tires back to Cycle gear and had them re balance them and to move the weight to the center of the rim because they had the weight on the ouside edge which I believe was the problem. I havnt ridden it since I made the change but will find out tomarrow if it made a difference.
 
Last edited:
I live near Willow Springs Raceway, in CA. I always buy race take-offs, from the one of the tire dealers at the track. They usually only have 2-5 laps on them, so they are nearly new. They are super cheap (under $50 a tire) and though the side tread is a little worn the center tread is like new. The tires are race ready, super sticky, well balanced, and if I can make one set last a couple thousand miles (I usually get from 1000 to 1800 miles on a set) then I am well ahead of the money curve by the end of the year... Its comical because folks look at the tires and comment that I must be a great rider to get the busa over that far. After a few minutes of messing with their head, I then tell them that it wasnt me...
 
Sorry for the quick jack but, XLCC, I hope you're considering coming up to the STAMPEDE in July!
Raydog
 
I would check upper and lower triple bolts for tightness, too.

You gotta lift the front and spin the front wheel and see if you notice anything. While the front is up, grab both forks and see if you can move them front to back, and sideways - any noticeable looseiness would contribute to your problem.

Also, if you dropped your front by a lot while leaving the rear at about the same height, you drastically changed the bike's geometry to be more aggressive, i.e. less trail, i.e. less stable.

I wouldn't bother with the damper for this specific problem. You shouldn't have a headshake even if you don't have a damper.

Also, what could give you a clue is the frequency of the headshake. If let's say at 50 mph the front tire makes 10 revolutions/sec, and you get about the same frequency of the headshake, then the source of the problem is the tire and not the steering.

The difficulty is that a minor irregularity of the tire can be aplified by the aggressive steering geometry.

Let us know what you find out.
 
check the tire itself, the pressure and the wheel weights first. I had this problem right after installing a new tire and complained enough to get a new one a problem solved.
 
Out of balence tire.
Here's what Kevin Cameron says on the subject.
Cut from Sportbike performance Handbook.
Fourth paragraph.


cheers
ken

wobble weave.JPG
 
UPDATE

i checked tire pressure and it still did it.
So i loosened fork springs 1 turn and it seemed to lessen it. I have these things super tight because i am 260 lbs. i am guessing i might want to just upgrade the springs and get rid of so much preload. AND I TYPICALLY LET GO WHEN I AM COASTING TO A STOP LIGHT OF FREEWAY OFF RAMP TO SIT UP AND STRETCH FOR THOSE WHO ARE CURIOUS.
 
your front tire is probably cuped, and also the left most side of it probably has uneven wear from the slop of the road, ect...my tire had some cupping in it awhile back, I aired it down about 2-3 psi less then what i was runing the problem seemed to go away after a week or so, and the tire no longer shows any signs of cupping...
 
You must log in or register to reply here.

Similar threads

tinbender0
Head shake
Replies
3
Views
1,320
tinbender0
tinbender0
L
head shake /tank slapper
2
Replies
28
Views
1,919
ozz
ozz
202mphbusa
carbon tank fitment
Replies
4
Views
766
202mphbusa
202mphbusa
nabusa
Head shake and bumpy ride
Replies
8
Views
1,739
dadofthree
dadofthree
justin726
What's causing these problems?
Replies
5
Views
652
justin726
justin726
Back
Top