Alarming Bike weave

Sgt Bilco · Jul 22, 2016

All

Got a bit of an issue with the old girl.

Riding through mist rain and a dirt road in the Yukon yesterday, the bike suddenly decided to start weaving slightly. I initially thought it was the road conditions but is continued. I then thought I had a front puncture but the conditions were appalling and there was no way I was stopping because the conditions were so bad and anyway Heidenau's are generally tough enough to not worry too much.

Anyway, on closer inspection this morning, the pressures are good and there are no apparent clunks from bearings or drive. Everything seems as it should.

The mud is horrible so maybe some was affecting something but after a jetwash and a removal of about 5kg of the stuff, no change.

Rode up and down and what is happening is the front end seems to have a mind of it's own and weaves left and right as if it wants to tuck. It dissappears when you get over about 40mph.

I'm presuming it's the tyres but I've never had anything like that before with Heidenau's.

Any one have any thoughts?

ymfb · Jul 22, 2016

are you heavily loaded, especially at the rear of the bike ?

Sgt Bilco · Jul 22, 2016

Not really but I've tried it empty and the same is happening.

Bungy · Jul 22, 2016

Are both fork seals ok?

MikeS · Jul 22, 2016

Have you checked the fork clamp bolts etc. Was the cause of weaving on one of my bikes once.

Ogmios · Jul 22, 2016

Not wishing to teach granny to suck eggs but, Is the tyre seated on the rim o.k?

Only time i had similar - it was a loose engine mounting bolt 'pushing and pulling' the drive as i accelerated or decelerated!

Good Luck.

(RIP) Tunneruk · Jul 22, 2016

Have you checked the teller lever balljoint?

MikeO · Jul 22, 2016

I'd agree with the advice above - if it's not load related, then the telelever - either the balljoint, the bearings where it enters the crankcase, the fork brace clamp bolts etc etc - is where I'd be concentrating my efforts.

JJH · Jul 22, 2016

old but true if the front feels funny check the back. JJH

gazza12adv · Jul 22, 2016

JJH said:
old but true if the front feels funny check the back. JJH

I agree with the above. In germany 4 weeks ago my mates girlfriend on her tuono said her front end felt really weird over the intercom. We stopped and I checked her front tyre and front end and all was good. I was getting on my bike again and noticed her rear tyre was flat.
CHECK your rear bearings etc

DrFarkoff · Jul 22, 2016

Bilko I am having a similar problem with my heidi's Sounds slight in comparison to yours

A weave which seems to be cured by sitting forward and putting more weight on the front

Its back to basics for both of us Sir

Checks I will be doing.....

Tele lever ball movement AND the top bearing below the Yoke, and check Fork Clamps are tight

Front Shock mount top and bottom

Swingarm bearings
Rear FD pivot Bearing
Brake disc carrier to Axle tube still tight
rear shock upper and lower mounts

and Test the Suspension see if you have lost damping OR a broken Spring !

Bungy · Jul 22, 2016

Really interested to hear the diagnosis.

Shep · Jul 22, 2016

Rear shocks fekked or something rear suspension related I reckon.
feelings of instability with the front end are often symptoms of a fault at the opposite end and visa versa.
Good luck its not a nice thing to experience (i would check the front pinch bolts as well)

John RTW · Jul 23, 2016

Just a week a go I had a similar although brief symptom happening to the Yamaha XT660r (and heavily laden) with Heide´s fitted. Turned out to be a slow puncture in the rear. Obviously not your scenario as you´d have noticed but one for others to keep an eye out for.

Sgt Bilco · Jul 23, 2016

Tunneruk said:
Have you checked the teller lever balljoint?

I think that's the fella. It looks like there is a small split in the gaitor and some very fine mud has got in. Not surprising really as the shit we rode through was nasty.

We had a good check of everything and generally yanked and tapped everything and all was good. I think we must have dislodged the dirt in the ball joint as a test ride had cleared up the problem. Will put loads of WD40 around teh joint and then get a new gaitor and get it chacked out down at Santa Rosa BMW in a couple of weeks

Fingers crossed that has solved it and thanks for everyones input.

Bendy toy · Jul 23, 2016

I replaced my top steering bearing when the subframe was powder coated.
Considering how unloaded it is compared to "normal" forks, I was surprised to find the bearing had tight spots. It would have been knotchy soon enough.

It had done 50K miles virtually none off road.

Sent via iPhone so expect strange words

patzx12 · Jul 23, 2016

A tight bearing would do it, I know tight head races on conventional forks cause weaves.

Bendy toy · Jul 23, 2016

patzx12 said:
A tight bearing would do it, I know tight head races on conventional forks cause weaves.

Cars have a large mass with a small percentage of steered mass.
Bikes are closer to being articulated vehicles and they use steering to keep upright. The steering has to be much more accurate. Stiff steering foils the self centring castor effect, the rider over corrects and a weave develops.
Those with normal forks will weave a lot more easily than a bike that separates braking and suspension forces.

Sent via iPhone so expect strange words

(RIP) Tunneruk · Jul 23, 2016

Tunneruk said:
Have you checked the teller lever balljoint?

Sgt Bilco said:
I think that's the fella. It looks like there is a small split in the gaitor and some very fine mud has got in. Not surprising really as the shit we rode through was nasty.

We had a good check of everything and generally yanked and tapped everything and all was good. I think we must have dislodged the dirt in the ball joint as a test ride had cleared up the problem. Will put loads of WD40 around teh joint and then get a new gaitor and get it chacked out down at Santa Rosa BMW in a couple of weeks

Fingers crossed that has solved it and thanks for everyones input.

Awesome ... I'll PM you the address to send my prize to ..

DING-DONG · Jul 23, 2016

Tunneruk said:
Awesome ... I'll PM you the address to send my prize to ..

Maybe he will buy you some indicators

Alarming Bike weave

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