Hi Guys,
need some help. My bike becomes very unstable when I go over 65-70mph, font wheel starts wobbling and handlebars start shaking. To see what happens I increased my speed to 80 and bike becomes almost impossible to handle. The closest description I can give, it is very similar to when you puncture you front tyre and bike starts zig-zaging??? (closest synonym???). First I thought It was my forks as one was leaking oil. But mechanic sorted that out and problem still there. Also the front wheel has been balanced bearings are fine too. I have knobblies on my wheels, but they are in good condition. Think I only done about 2500miles on them. Middle ones are a little bit more worn than side ones.
If slow down to 60 and less. Bike is fine, but my confidence is going even on short rides. Any suggestions?

Thanks for your help.

Just in case here's a link to the tyre photo

https://picasaweb.google.com/lh/phot...eat=directlink

Vadims

A mate of mine had the very same problem, it was related to the tyre.
He was describing his....similar to a tank slapper.
It just seemed to correct itself after a good few miles.
I know he never changed anything although he did put some slime in his tyre to prevent punctures and that may have corrected the problem.
I do know it did not help him when riding the bike.
Hope this helps

steering head bearings lose... spoke tention..wheel balance..'front & rear"
Another place people don't look is fork springs..If one has lost its tention it will put more load on the other causeing the wheel to sit slightly side ways....swing arm pivit...
dose the wooble change between on the power / off the power?


I had lose spokes on a RD350 rear wheel years ago... I couldn't slow down..under power the rim tracked straight...Off the power the rear went evertwhere.. Only way I could slow down was lock the rear wheel up with the brake..if it wasn't turning it wasn't a prob...

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Harley Davidson..
The easyest way to turn gasoline into noise with out the side efect of horse power...

In addition to the above...

Have you got the basic suspension settings correct? Too much sag/too little preload (or a knackered shock spring) at the rear will cause bad headshake, more so at higher speeds where the wind acting on your body transfers more weight to the rear. A lot of high speed wobbles and tank slappers can be sorted by getting more weight over the front, add preload to shock, raise the fork tubes through the yokes 5mm at a time. Too little sag on the forks and too much front rebound damping will have the same effect (although this is less likely in your case, unless that is you've changed things up front (fork spring spacers, more viscous oil, changed the air gap etc.)

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First of all what miles has your bike got?

How many miles has your front wheel been on for?


First off when your front tyre wears it doesnt wear evenly so will wobble a bit but normally you will not notice this untill its quiet big like yours is now. If a wheel weight comes off it will give you the same feeling but very instant change. Or if your head race bearings are worn so much this will also give the same effect but this takes a good lot of miles or failed wheelie attempts to wear them out.

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Plough on

Tyre pressures can make quite a difference to whether a knobbly front will wobble at speed.

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I spent a lot of money on travel and racing motorcycles - the rest I just squandered.

XT660Z - Commuter, Adventurer...Racer?

www.dashmoto.net

Other bikes >> MT-03 / CG125BR-J / ER-6F
Departed >> ZXR400L3 / EC300 / DR-Z400E / DR800S / GPZ500S / GS400

I had my bike serviced today
I did had a wobble at 65 but now its worse at 65 i pulled the bars tight and it settled down the faster i went the harder it got the guys have pumped my tyres up will check psi when i get home and adjust will reply and see how it is

I am fitting hyperpro springs kit it has a thicker oil too the front forks on the xt are way too soft ::


Xt660x 04

Time perhaps for a gentle service of the front end suspension ie change fork oil and fit Kev spacer will help????

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(Now sold on, sob) 2011 Blue XT660X with gold wheels, was 26,500 km.
Engine mods: K&N Stage 1 filter, DNA Stage 2 filter, snorkel removed, Kev fuel mod fitted.
Plus: smoked Puig screen, Yam aluminium sump guard, Yamaha / Acerbis handguards, Givi Trekker aluminium side cases, Leo Vince X3 cans plus Kev front fork mod and Fender Xtender. Just fitted Michelin Road Pilot 3 tyres.

SOLD the XTX for a Super Ten 1200. And just bought a Raptor 700 so staying on here for some tips....

Asked kev about the spacers there no longer available :/ hyperpro do a springs kit with oil �115 thats my next mod


Xt660x 04

Just lower the pressure to 28psi and you will send me a check of �xxx as a thank you muchly! I guarantee you.