Front end wobble

[roger_doger]

Hi Guys,

I rode a friends 1989 CBR1000 yesterday, and it is a great bike, however it has quite a scary vibration/wobble coming from the front end under certain circumstances.

1. When you're doing about 70km/h and let go of the handlebars, the bars progressively start to shake violently from side to side, kind of like you have a flat front tyre.

2. At speeds over 150km/h, the front seems to be vibrating enough to make you concerned, if not a bit nervous. When you look down at the forks, they APPEAR to be moving back and forward very quickly, however this may be an illusion.

Has anyone experienced this before or have any ideas on what to do?

Cheers

[Grub]

I'd certainly go for wheel balance to begin with. That sort of action can lead to a tank slapper which is down-the-road material. After that I'd get someone to be looking at shocks and springs, maybe summat's broked

[dino3310]

hows the front wheel bearings and the steering head bearings,i'm no mechanic but thats what i would look at first,get the front end of the ground with no weight on it give the front wheel a wiggle if the bearings are gone you should see movement on the shaft,same with the steering head,could be a loose nut & bolt on the front end.if theres nothing obvious i would definately get it to a mechanic before it gets to serious a wobble.
i was getting the wobbles on a xj600 between 80-100k,turned out the steering head nut was a little loose, tightend the steering head half a turn problem solved.

[riffer]

Yeah, sounds a lot like steering head bearings too loose.

Don't discount the tyre as well; tyre pressures and balance can play a big part.

But I'd definitely start with the steering head.

[Blackbird]

Don't suppose it has an Avon Storm front tyre fitted, does it? It doesn't quite look like the symptoms exhibited by some Storms, particularly the first shipment into NZ, but it would be good to rule it out as a cause.

[NighthawkNZ:Me]

All of the above advise as well as, does the bike have any aftermarket gear hanging on the rear subframe which can cause the front to wobble... ie

Exhaust
Panniers
pac rack

(Had the same problem years ago till I realised it was my panniers had a vabration, which was enhanced tillup front and I had to strengthen the sub frame)

[roger_doger]

Thanks for the info guys, I will pass that info on. The guys a newly born again biker and just bought the bike, so it would be good to keep him enthused.

The front tyre is a Shinko, though I'm not sure what model. There is no extra gear on it, it's basically a bog standard bike.

[NighthawkNZ:Me]

Thanks for the info guys, I will pass that info on. The guys a newly born again biker and just bought the bike, so it would be good to keep him enthused.

The front tyre is a Shinko, though I'm not sure what model. There is no extra gear on it, it's basically a bog standard bike.

It is most likely bearing of some kind, wheel beering, steering head bearing... but I would start with the basics... wheel balance, check tyre pressure, new tyre etc...

[Central Wheel]

Hi Guys,

I rode a friends 1989 CBR1000 yesterday, and it is a great bike, however it has quite a scary vibration/wobble coming from the front end under certain circumstances.

1. When you're doing about 70km/h and let go of the handlebars, the bars progressively start to shake violently from side to side, kind of like you have a flat front tyre.

2. At speeds over 150km/h, the front seems to be vibrating enough to make you concerned, if not a bit nervous. When you look down at the forks, they APPEAR to be moving back and forward very quickly, however this may be an illusion.

Has anyone experienced this before or have any ideas on what to do?

Cheers

Hi bud first thing is to check the things that dont cost you a penny, Ie wheel bearings then steering head bearings that can be done by sitting on the bike put the front brake on hard and rock the bike forward/backward and listen for a knocking sound! if you live in auckland come to my shop and ill test the balancing for nothing just to make sure your riding a safe bike #0210528984 cheers Mark.

[roger_doger]

Hi Mark, Thanks very much for your offer of a free balance. I am in Palmerston North so won't be able to take you up on that unfortunately, but thanks for the advice all the same

Cheers

Phil

[F5 Dave]

What was said above is good advice, but often that sort of thing is more prevalent from the rear tyre being worn.

Also in addition nice if the wheels are somewhere in line. A straight edge is a good idea as the marks on the sw are often bogus from new & worse if bike crashed in last couple of decades of it's life.

CBX550s used to do this shake on the slowdown from 70 with no hands from new to some extent but got worse as various things wore, esp tyres. They updated the head bearings but it was a feature.

WTF are you doing at 150 on what sounds like a deathtrap? -'specially on those bump manuatu rds. (Higher speed sounds like balance, but could be a few things like out of round tyre/wheel) Get the bike sorted, probably needs a good going over to check all bearings & rebuild suspension before any performance is released. They may seem like a lardy old bike but they can bite & were very capable in their day (and quite a nice bike to ride), but that was ~ 20yrs ago.

Not sure of bike shops up there but Pete at Total MC knows his stuff. Can be expensive, but you are paying for a better than average knowledge.

[notasothers]

The exact same thing happened on my mates 89 CBR.

Long story short....Turns out it was loose steering head bearings.

[codgyoleracer]

Incorrectly beaded tyre, steering head bearings worn - check, loose steering stem check, wheel bearings check, tyre pressure check, stiction in one fork (bent) check, wheel bent / fault check, bent top or lower front clamps - check.

[Reckless]

To add to the above.
I had a new tyre fitted at cycletreds once and it developed a wobble at 120k on the old Z. Nothing major and when you tipped it into a corner no wobble. I discovered they hadn't seated the axle properly under the forks.

So when you strip it to check the wheel berings etc check this as well.