Strange vibration / wobble.

[stumpi]

Hi all,
Had my 2010 30 years 800 for a week now and on the whole I'm really pleased with it, it's everything I expected it would be and wanted.

However, I have noticed a bit of a strange wobble or vibration at slow speed, and it's enough to unbalance the bike to the point where I have to stop.

I'll explain, I'm pretty good at balancing bikes, it's a talent I've had on mountain bikes and motorbikes for years and what I like to do is trickle, extremely slowly to the point of standstill momentarily at lights and junctions so as not to put a foot down. The problem is, that just when I get to that point on the 800 it develops a sideways wobble or type of vibration that's enough to unsettle it's balance, just at the crucial near standstill point where you'd balance the clutch n brake a little, that enevitably means I have to drop a foot. It's made very low speed filtering up to lights quite difficult in some circumstances.

I'm just curious if this is a common trait of the bike or if I have something strange going on with it. If the bike was an 1150 I could understand it as they have this slight side to side feeling sometimes due to the boxer configuration but as the 800 is a parallel I'm a bit stumped. Any ideas what I'm experiencing, and is there a cure?

Thanks for reading,

Stumps.

 

[rce]

What tyres and how worn are they

 

[stumpi]

K60 Scout and they're pretty fresh with a couple of thousand Ks on them.

I'm not sure it's tyres, although do bow to superior knowledge, it really feels like a mechanical, motion. And high up so as to cause the wobble.
I'll give it some more thought/testing in the morning and try to think if it might be the tyres.

Thx btw

 

[bondyzf]

Steering bearings

 

[colint]

Steering bearings

+1 Steering head bearings, what mileage has the bike done? look at the threads on this forum.

 

[stumpi]

Thanks guys,
Definitely not head bearings or tyres.
Its a mechanical side to side motion. At low revs just above tickover and is most noticeable when youre on the fine balance at very low speed.
Head bearings are fine, I've just checked em.
Any other thoughts?

 

[rce]

Think it is probably the tyres, something I have read a few times hence my question http://www.advrider.com/forums/showthread.php?t=799490

 

[stumpi]

Hmmm, that's very interesting, thanks.
I'll try different pressures to so if it makes any change.
My wobble is at below walking pace but it sounds like the same thing those guys are experiencing in the feeling.

 

[stumpi]

Just reset the tyre pressures, rear was a bit on the high side so dropped it to the handbook spec, also looked at the tread pattern and on closer inspection it is staggered in such a way that the vibe could be coming from there. Will see in the morning. While I was at it I took the front wheel out and balanced it, needed an oz and a half to sort it.
Then fitted my Sw motech light mounts, Mudsling and fender extender and generally fettled about with it
I now Remeber why I loved my 1150s so much. There's just constant tickerability with these bikes, love it.

 

[stumpi]

So I can confirm it is the tyres, and it comes from the rear!
How can I be so sure?
I have a friend who has one on road tyres so we swapped em about a bit, swapped the rear out of mine leaving the K60 up front and the wobble was gone!
I'm ok dealing with this now knowing the bikes ok. A little
Bit of a pain but can be lives with until I need to replace them. Might go for TKCs then, they were awesome on my 1150.