Handlebar wobble... tank slapper?

[Guest]

Hi all, well quite a while ago i noticed if i take my hands off the handlebars, they wobble.

But, only recently, i decided to see the extent of the wobble, i counted to 4-5 seconds, and the bike was nearly in a full blown tank slapper.

Why is this? tyre pressures are ok, and chain is tight... dunno what else could cause it. Passed its MOT like this so i wouldn't see bent forks, although the yoke/clip ons are slightly not straight... maybe that?

Cheers all

[Hoody]

Could be that you take your hands off the 'bars??!!?

[eastanglianbiker]

are both bar end weights the same check condition of tyre for bulges check play in headrace bearings

[duane69]

have a look at the head stock bearings

[Guest]

Ahh, the head bearings.... I hear a slight knock when i break quickly at slow speeds too.

I guess its going!!!

Hard to fit a new one?

*whiny voice* "Fraaaannnkkkiiieeeeee????

[eastanglianbiker]

you might be able to adjust the bearing by loosening large nut on top yoke then get thin chisel into the lock nuts and gently tap round then tighten large nut again and check for play dont tighten lock nuts to much do little at a time and check movement of handlebars from one lock to the other or put weight on back of bike to keep front wheel in the air grab both forks low down an see how much if any backward and forward movement they have

[Guest]

Could also be the suspension isnt correct!

Do remember though eventually they will wobble if you go too slow

(i usually start going to the left/right too much and am forced to hold on lol)

[Ingah]

Head bearings are easy to check.

Pop the bike on centre stand.

Get someone to put their weight down on the back, which will lift the front wheel slightly off the ground. Ensure that they keep their weight on it, otherwise it'll be very difficult to feel any play!

Turn the wheel from side to side slowly (do it a few times to be sure) - if your head bearings are done then then you'll feel a small notch in the middle (most travelled bit) - almost like it's slipping into a comfty spot (in actuality it's a groove worn into place by constant rubbing). It could also feel notchy on the turn. If either of these are the case, they need attention (and are probably MOT fail, unless the MOT is hooky )

Obviously ideal/good is when it moves smoothly through the entire travel.

Also, are your forks doing their job properly? Get on the bike, apply front brake hard, and then push the bars forwards a few times, hard (they'll sink down into the forks). Are they going down and coming back up smoothly (good), or notchy (bad, probably MOT fail)?

[PhatDad]

My dads has been the same for years however I came off it in June/July and since then it's fine. I cured it so my suggestion is have an off to sort it. Although, it could have been the fact the top box isn't on it anymore as it smashed up on impact or it did something to the suspension. In fact I've probably been no help at all here.

[Phill_vtr]

The cockroach is just the same as is my mates ER5, be nice to know what it is though

[Fozzie]

Sounds like head bearings have gone,

There should be 2 of them, one lower and one upper. Its quite difficult to replace in that you have to support the bike well as you are essentially taking the front of the bike off

They go quite quickly on the GPZ and the GPX for that matter.

[Guest]

Cobbz, it could be anything from uneven tyre wear to a bad bit of road, head bearings to misaligned forks (one slightly higher than the other), even an unbalanced rider or pillion..

if you want to check the head bearings, have a read of a manual, and if replacing get Needle bearings, these are now standard fit, whereas they used to be ball bearings.. (like your pushbike) ball bearings were horrendous for giving notches in the head, (think ball hammer hitting a piece of metal.. this is what the balls (bearings) were doing each bump and pothole in the road)...

Link to a GPZ500s Manual

http://www.themotorbikeforum.co.uk/view ... 27&t=22733

[Guest]

Cheers frankie. Well, i tried the turning side to side thing, and theres no notch, BUT, i can push the forks back and forth a tiny bit - literally millimetres.

I've got the manual and a haynes, lucky cos that link doesn't work anymore mate! Said it was removed by copyright.

Could the new top box have something to do with it? I know it isn't exactly perfect

Is there a way i can straighten the handlebars? The forks look fine, but the handlebars are twisted to the right.

[Guest]

pic of the bars?

could be a replacement bar or a ebay search...

[Guest]

they're clip ons, its like the yoke isn't straight or something... I'll get a pic tomorrow.

If its gonna be expensive, i won't bother cos its not a problem really, but i would like it straight, lol.

[Fozzie]

I had the problem with the bent clip ons, just undo the bolts holding the yoke tight on to the forks and then with a fair bit of strength apply a good amount of pressure in setting them right. Jobs a good un

It worked for me and I aint exactly built like a brick shit house now am I?

[Hoody]

Wheel bearings too - check them, had a similar isue on a Blackbird.

[Guest]

Well, on Wednesday i found out it was indeed the rear wheel bearing that was causing all this.

When i got my tyres changed, the wheel bearing basically fell apart into his hands. The bracing used to hold the ball bearings in place, had just shattered, and the remains and mashed itself into the wheel. Bad times!

Anyway, nice shiny new one for £8, nice new tyres, and not even a tiny wobble

[Guest]

Glad to hear it Dan

And for £8??

Deffo glad to hear it!!

[Phill_vtr]

I think I found the answer to my problem too

http://i51.photobucket.com/albums/f397/Phill_VTR/IMG_0456.jpg

That would have happened when I hit the deer last year. oooops