Help - GSXR750 speed wobbles

**GSXR_BIKER** · 29th July 2008, 21:59

Hi All, bit of advice needed. I was riding my old GSXR750 (Loving every minute) took it up to 90kph and the handle bars started violently moving side to side, (I think they call it tank slapping), when I slowed down to 60 it stopped, but started again when I took it back up to 90???

Only thing I can think of is that one of the front shocks had died, as I put all new bearings in the front wheel when I did the bike up.

Any way, Its far too fun going fast, so I need to get this beast back in the fast lane. Any suggestions would be great (Wheel is on tight)

Ta Muchly

**howdamnhard** · 29th July 2008, 22:03

Front wheel balanced?

**boomer** · 29th July 2008, 22:05

flat/under inflated/bald or not balanced tyre, head bearings.

either way, harden up and go faster; Its a speed wabble not a tank slapper.

**Jantar** · 29th July 2008, 22:15

I agree with Boomer. It certainly sounds like a tyre problem. How old and/or worn is the front tyre? Is it balanced?

I would check the front tyre as a first posibility, next stearing head bearings, and then look at the front forks, suspension, frame.

If it was a genuine tank slapper, you'd be more likely to be telling us about your crash.

**Shadows** · 29th July 2008, 22:27

Have you checked your steering head for tightness? Any grease in there?

Steering head bearings or races fucked?

No cracks in the welds or frame around the steering head?

Fork tubes loose in the triple clamps?

Front wheel balanced?

Front wheel straight?

Sticky brakes?

**boomer** · 29th July 2008, 22:36

Originally Posted by Shadows

.... or races fucked?

que?

Originally Posted by Shadows

No cracks in the welds

He has an older model Gixxer.. he should be ok

**Shadows** · 29th July 2008, 22:57

Originally Posted by boomer

que?

Races is wot the bearings sit in. If they be fucked everything could be sloppy.

**AlBundy** · 30th July 2008, 02:23

When did the shakes start?

Before or after you did the wheel bearings?

Is either fork leg leaking oil excessively? If it is, the seal is gone, if not, unlikely the leg has died...

**DEATH_INC.** · 30th July 2008, 05:20

Originally Posted by Shadows

Have you checked your steering head for tightness? Any grease in there?

Steering head bearings or races fucked?

This would be my guess, check them NOW before you ride again. This situation can lead to a quite bad crash if it all goes wrong.

**Kiwi Graham:Me** · 30th July 2008, 10:07

Before you get on this bike again...... check you stearing head bearings, use a jack and lift the front wheel of the ground or do the tip it on the side stand trick (either way you need a mate to steady the bike) and grab the front wheel and push and pull it (side to side play will be wheel bearings). If you feel any movement adjust the bearing by gently tightening the top ball race nut, check again also making sure by turning the bars (disconect stearing damper if you have one) there is no clunking/roughness. If all seems ok front tyre is the likley cause, either too soft, worn or un-balanced. Check the back tyre too, it's weird front end problems can sometimes manifest from the ass end!!!

**Chrislost** · 30th July 2008, 11:01

Originally Posted by GSXR_BIKER

Hi All, bit of advice needed. I was riding my old GSXR750 (Loving every minute) took it up to 90kph and the handle bars started violently moving side to side, (I think they call it tank slapping), when I slowed down to 60 it stopped, but started again when I took it back up to 90???

Only thing I can think of is that one of the front shocks had died, as I put all new bearings in the front wheel when I did the bike up.

Any way, Its far too fun going fast, so I need to get this beast back in the fast lane. Any suggestions would be great (Wheel is on tight)

Ta Muchly

did you do the head berings?
wheel is round?
by violent do you mean moving or wacking your hands against the tank
if its wacking your hands(tank slapper) then take it to a shop to fix.
if its just moving then check the wheel weights have not fallen off, loosen the pinch bolts and tap the axle with a hammer(softly!!!) to make sure its centered in the forks.

you could always do the GSXR thing and wheelie everywhere?

**Timber020** · 30th July 2008, 11:51

My guess is lack of air in front tire, I had a slow leak in my front and would wobble at 160, then wobble at lower speeds with the tyre loosing pressure

**chrisso** · 30th July 2008, 14:25

sounds like my ol GSX1100..... bad bad wobble over 140...went away 2 up.
Tyres?? Bearing? rear wheel alignment?

**xwhatsit** · 30th July 2008, 14:28

Don't forget swingarm bearings as well -- I don't think anybody's posted that yet. Put it on centre stand, then tug the swingarm or rear wheel side to side. If you can see any movement, you need new bushes.