Shuddery vibrations on a motorbike.

I recently took off the wheels (Zed thou) to paint them an of course, I had
to remove the discs. Now being a stupid **** I didn't mark them "left" or
"right" even though I thought it would be a particularly good idea.

On rebuilding the bike, everything went swimmingly (always a bad sign, that)
but come the first ride the bastard vibrates like an Ann Summers rep on
speed when I use the front brake. So the question is...

Fucking obvious really, but, would the FOAK say I'd put the discs on the
wrong side? And that's not a suggestion on what to say either, for you
pedants.


--
Beav

VN 750
Zed 1000
OMF# 19

 

You did of course mask off before to painting/remove the paint from the disc
mounting area on the wheels prior to fitting the discs?

JB

 

My guess is that either you have bent the disc(s) whilst they were off the
bike, or you have dirty under the mountings points which is causing one of
them to run out of true..
It should be easy to check... with the front wheel raised spin the wheel,
the effort needed to turn it should be even with no tight/lose spots..

 

Presumably you have had the wheel out before (without disturbing the
discs) with no similar problem. In the bad old days you were always
advised to 'lunge' the forks up and down well before tightening
everything up finally. You would have noticed 'stiction' as well though
if something was slightly misaligned.

Is it a calipers off job to have the wheel out? No doubt you have
double checked the caliper retaining bolts.

 

No. I'd guess you tightened up the disc bolts unevenly, and warped the
disc. Or both discs.

 

Have you bled the brakes?

 

<Baffled>

What difference would that make?

 

(The Older Gentleman) wrote in
message

From memory this chap's a fuckwit so I wouldn't worry too much about his
posts.

 

As well as the obvious dirt/paint under the disc mounting surfaces,
check that the fork bottoms, if they undo, are tightened correctly and
that the axle bolt is also tight and all spacers/bearings are in their
correct positions and the right way round.

 

Beav wrote

If it would make you happy I don't see why not.

 

Beav says...

Did you have the tyre off the rim, and if you did, is it back on the
right way round?

I had this problem when someone fitted a tyre to my GS550, put it on
wrong way round and it only juddered on braking.

 

They're definitely sat as square as possible. No paint near the mounting
surfaces and wheel/discs cleaned with thinners before re-assembly. I used
bloody Loc-Tite too


--
Beav

VN 750
Zed 1000
OMF# 19

 

I did of course.


--
Beav

VN 750
Zed 1000
OMF# 19

 

I doubt that lying them on a foam pad in a drawer for the duration resulted
in anything being bent.

or you have dirty under the mountings points which is causing one of

Definitley no dirt, no paint, no tape edge, so it looks like I simply put
them on the wrong side. I'll know on Monday when I swap 'em aound.

I've not got me front wheel raiser at home and unfortunately, that's where I
am, but I'll be checking for out of true first thing Monday.


--
Beav

VN 750
Zed 1000
OMF# 19

 

Yeah, a couple of times when the tyres have been changed. Never a problem
before.

In the bad old days you were always

No stiction, just a vibration and it's fucking horrible.

Always. With them in situ, the wheel won't pass between them.

No doubt you have

Anti-seize compound and tightened with a torque wrench to Kwak specs.


--
Beav

VN 750
Zed 1000
OMF# 19

 

message

If I was a total beginner at tightening flimsy circular things, I'd go along
with that, but I'm not, so the discs were tightened in a X" pattern to
avoid/minimise the chances of any warping. I was even explaining why I'd
done it that way to an enthusiastic Ped-Boy so he didn't warp his own disc
if ever he had to remove/replace it.

I'm thinking it's GOT to be that the discs are on the wrong fucking side,
due to my numptie memory.


--
Beav

VN 750
Zed 1000
OMF# 19

 

No, but why would I need to? No fluid was injured or lost in the production
of this paint job, so no air got in the system.


--
Beav

VN 750
Zed 1000
OMF# 19

 

I'll be pulling the discs off again on Monday, so I'll be checking all of
the above. I didn't give any thought to the forks, I have to say, but the
axle "fell in" without any need for a Birmingham screwdriver to persuade it
and both spacers were immediately placed on the axle when it was removed so
I didn't need to remember spacer orientation. They went back exactly as they
came off.

I bet I find something on the discs that say "This way round", or "Rotates
in this > direction" and I missed it. Nah, that'd be too fucking easy


--
Beav

VN 750
Zed 1000
OMF# 19

 

No Loz, tyres stayed on. I had them balanced afterwards though, coz I did
remove the original balance weights

I checked on the tyre for the direction arrow (when I rebuilt and after the
ride) and it's apparently as it should be, but I'm thinking there's a
fucking arrow on the discs somewhere (hiding).


--
Beav

VN 750
Zed 1000
OMF# 19

 

Quite likely.

I pulled the cams out of my Z650 engine last week, and on removing the
first cam looked at it thoughtfully, grabbed a bottle of Tippex and
marked it IN. Then pondered some more and marked L and R at the relevant
ends of the cam.

And the exhaust cam got EX, L and R as well. Just in case. because if
they're ever to get re-fitted, five years down the road, by me or
someone else if I sell them, they're certain to get put in wrongly
otherwise.