Blackbird problems

But are we agreed that the statement "Most bikes do this at that speed,
faired or not..." is bollocks and I was just a bit out with the reason for
instability[1]. Not that I don't admit there are *some* bikes out there
that can be a bit unstable, I'm just not convinced that it's *most*...

Dave

[1] And I would still argue, mildly, that if the tyres are worn then it's
likely that the wheel is out of balance amyway as they're normally only
balanced when the tyre is new...

 

Hmm, that is a bit picky.
Surely, if the wheel was no longer properly balanced, I would feel a
slight hammering through the bars at, ahem, higher speeds?

The GTS has a newish front tyre on it, I'll try tomorrow to see if it
still does it.

 

Thinking back, I once had a MkII Escort that had cronic steering wheel
wobble. The wheels were ballanced, but the tyres and wheels came off
another car and were a little strangely worn.

 

more like firstly.

 

You missed the usual culprits. Swingarm bearings.

 

Gordon Hunter wrote

Snot an import is it? Might need the camber bearings doing if it is.

 

As far as the winds are concerned, swap the tank bag for a tailpack
(try borrowing one first) and go and try it again. The BB is
notorious (along with the ZZR1100) for funny behaviour when you
disturb the air in front of the rider. Dunno why, it just behaves
better with the luggage behind you than in front.

Anyway, it worked for me, although the wobble at 45 to 55 - not sure
about that.

 

A couple of my mates honestly think I have tourettes. The cunts.

 

My 4000 mile-old VFR800 did. Like a fucker. And the wheel wasn't out
of balance.

 

That's true. Wheels do go out of balance. But a handlebar side-to-side
shake is unlikel;y to be down to an unbalanced wheel.

 

Usually between 50 and 70; they tend to smooth out at higher speeds.

 

My MZ Trophy will do it at 30mph loaded up - which is jolly
disconcerting. Having the tyre pressures above 15psi helps in this case.

To add my 2d:
Assuming the tyre pressures are above 'flat' weaves, wobbles and shakes
are usually caused by worn or poorly adjusted chassis bearings (head,
wheel and swinging arm).

Wheel balance is a hammering only noticeable at a fixed speed range.
Usually 50 - 70mph.

 

Well my bandit started hammering at ~ 100 when the balance was wrong.

 

Kiran wrote

It would do it on mine but only when I had a topbox on the wingrack.
When unladen it was fine hands off the bars. Mind you, the front 020
was a bit worn.

Yep. See above

Yep, it's a bit slabby so is affected by cross winds, it's easier if
you're over the tank as you have a smaller/less sail-like profile.

Cheers,

Paul.

 

Rode mine back from Llandudno this weekend and it was quite windy,
I always get "shake from side to side" if I let go, so I stopped letting go

I had Givi top box and Magnetic tank bag fitted

No real problem just live with it

--
Vass
................................................
Now: YZF-R1, CBR1100xx-x (camera bike)
Then: A100, MBX80, XL125, CB400, FZR600, CBR600Fv
http://europebikerun.textamerica.com

 

It was somewhere around Barstow, on the edge of the desert, when the

Don't you start; I'll take you all on, y'hear?

I lumped that under 'rear susp'.
I didn't forget.
Honest.
Harummmph.

--

Dave

GS 850 x2 / SE 6a
SbS#6 DIAABTCOD#16 APOSTLE#6 FUB#3
FUB KotL OSOS#12? UKRMMA#19 COSOC#10

 

MIIIIIAAAAAOOOOWWW!

OOH ya bitch

I was only just legally road riding by the end of the '70's y'know.

 

heh. I crashed my first bike with an hour of riding it, and twice the
next day I think, too.

 

Took me 19 days to lob my CBR600.

 

I crashed my sisters boyfriends bike before I got mine )