What feels like a flat tyre but isn't?

We just headed out in the general direction of Wales for the weekend
and have come back because the FJR feels 'orrid - just like it has a
flat. It feels unstable, definitely lurched as I did the u-turn and
if I take my hands off the bars while going along the bars begin to
shake quite violently very quickly - not something it's done before.
It's bad enough that I felt something was wrong as we were heading up
the gravel drive.

Pressure in both tyres is OK. Wheel bearings feel OK to me (not that
that's any guarantee as I'm no mechanic). There's no problem with the
suspension as far as I can tell from bouncing the bike.

Last time I took it out was for a rather long day just under a
fortnight ago and it felt fine when I got back so I assume whatever it
is happened while it's been standing there.

My local workshop is going to have a look at it in the morning but it
would be nice if I could figure it out first.

(I know it's going to be difficult to resist making comments about
FJRs always feeling 'orrid, going to Wales is the mistake and don't
take my hands off the bars but can we just take those as read?)

Kevin

 

on the R-GS some play in the paralever bearing made handling horrible. Not
sure what arrangement there is between the final drive & frame on the FJR
but there must be some sort of bearing. My mechanic adjusted it out on the
2 occasions it has happened in 50k.

 

Bearings or the tyre has developed a fault.

--
Veggie Dave
http://www.iq18films.co.uk

"To assert that the earth revolves around the sun is as erroneous as to claim
that Jesus was not born of a virgin." Cardinal Bellarmine

 

"If you think it's the front end, it's always the rear".

 

Dunno the bike personally, but ...

I'd start with a very good look at how tight the wheel axles are, and
whether anything has actually broken, like a spacer or stiffening
brace. Then check the head and swing-arm bearings. Get the wheels off
the ground and try to move each wheel side to side and backwards and
forwards, which might also check the wheel bearings at the same time.

If all Ok then move on to check frame joints and welds for cracks/loose
bolted joints.

 

"Kevin" wrote in message

three of us had this coming out of a tunnel in Swiss land
we all stopped, discussed we all had the same feeling
decided it was the road surface
10 miles later all returned to normal.
prob not helping, but thought I'd throw it in there
GL

 

Dunno about the FJR specifically, but does it have a control arm on the back
swingarm?

 

snip>

Both of my my FJs do exactly that when the front tyre is getting down to
near the wear markers.

JB

 

I had this on the ZRX some time back, and it turned out the tread
pattern on the front had worn in a kind of scooped out pattern on
alternate sides trailing the wavy line in the tread.

Happened I was about to get new tyres on the 10R, so I stuck the ZRX
front wheel with me on the pillion seat and had them fit the 10's part
worn dunlop to it at the same time. Handling returned to normal.

YMMV

 

The mechanic took it out for a ride and agreed it didn't feel quite
'right' which was good as I was concerned I was only noticing it
because I know how it normally feels. It was much better at speed than
it was at 35-50 which is all we'd done yesterday.

The wheel and steering head bearings are fine, the tyres, PR2s, have
only done around 1600 miles and don't appear to have any strange wear.
Suspension and linkages and are all fine.

I took it out for a ride without the panniers and it felt much better.
We've done thousands of miles on this bike with top box and panniers
on and they have never been a problem so it's not the panniers
themselves, they must just be manifesting the issue.

We were about to change the tyres one at a time when the mechanic
spotted a large dent in the rear wheel. It's large enough that I'd
have thought I'd have noticed hitting something that hard but I don't
remember such an incident. The dent put the wheel put of balance so it
was re-balanced.

This doesn't really fit the symptoms L and I both felt yesterday but,
while it still doesn't feel quite right - there's an odd vibration, it
feels much better, so we're going to head off to Wales and see how it
goes.

Apparently the wheel is quite safe but I'm not happy riding round with
a dented wheel so I'll be looking for a second-hand replacement or
some sort of repair when we get back.

Thanks for all the suggestions.

Kevin