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Post Subject:

handlebar alignment

Reply from: seabreeze
Date: 27 Oct 2007, 17:09
Re: handlebar alignment

On 27 Oct, 15:13, Morrgaine <Morrga...@gmail,com > wrote:
> On Oct 27, 3:02 am, seabreeze <corrie...@yahoo,com > wrote:
>
> > Took the bike back, they put it on their machine (not quite sure what
> > kind of machine it was, but something to do with the alignment) and
> > said it is all true.
>
> Perhaps it was a laser machine that checks the chassis alignment.
> Lasers work better than the old string method where the rider runs a
> 30-ft length of string through
> the back of the rear wheel, then walks the ends of the string around
> the back of the
> motorcycle, coming out with the opposite ends of the string in the
> front.
>
> Then the rider pullts the string tight so it touches the edges of the
> rear tire in four places and he eyeballs the distance between the
> strings and the front tire on both sides.
>
> Since the front tire is usually narrower than the rear tire, any
> lateral misalignment shows up on one side of the string being further
> away from the tire than the other side.
>
> When I do the string method, I tie the front ends of the string to a
> cinder block to hold them tight while I use a ruler to measure the
> distance from the string to the edges of the front tire.
>
> The string method only shows *lateral* misalignment, it doesn't show
> *vertical* misalignment.
>
> The rear wheel is supposed to be vertical when the motorcycle is
> travelling down a level, uncambered road. And the front wheel is
> supposed to be vertical at the same time and the handlebars (if they
> haven't been been in a crash) are supposed to be at 90 degrees to the
> front tire when the front tire is pointed straight ahead.
>
> So, old time riders would set the motorcycle up on the center stand,
> or prop it upright if there was no stand, and they would lay down in
> front of the motorcycle on their belly and look at the front tire and
> see if the saw more of the rear tire on one side of the front tire, or
> if the front tire wasn't vertical.
>
> If front and rear tires aren't vertical at the same time, the
> motorcycle will run down the road like a trotting dog. If you've ever
> watched some dogs run, you may have noticed that they run with their
> hind legs a little off to one side from their front legs.
>
> When a motorcycle has lateral misalignment or vertical misalignment,
> it will shake when you go over bumps.
>
> They said they slightly adjusted the windscreen
>
> > position (??).
>
> Yes, it sounds possible that a handlebar mounted windscreen could be a
> little misaligned to the handlebars.
>
>
>
> > The background to this is that the day I had the work done, I said I
> > wanted the steering head bearings replaced as it was an MOT failure on
> > just this, and took along the failure notice for their information.
> > I took it out yesterday and my impression is still that it doesn't
> > feel quite straight somehow, but that I could get used to it. On a
> > normal downward road camber to the left it feels as if it is pulling
> > slightly right, and on a down camber to the right it feels straight.
>
> Do you usually ride as far to the left as possible? The front wheel
> will try to climb up a camber and it will wear out the right side of
> the front tire. In the USA, it's opposite, we keep right and the left
> side of the front tire wears out first.
>
> > It could be that the bars were somehow already not quite straight,
> > although there are no signs at all of the bike having been dropped,
> > that the bars are not quite central by a small amount (which is how it
> > appears and would be easy enough to fix myself), or that as suggested
> > here, there is something up with the alignment following the repair.
>
> It's possible for tubular handlebars to get bent up on one side or
> backwards. You can visually inspect for an up bend by standing in
> front of the motorcycle when it's on the centerstand. You can see a
> backwards bend by standing above the motorcycle when it's on the
> centerstand.
>
> When I do a home inspection, I use string and I use a tape measure. I
> measure from the center of the front axle of both sides back to the
> motorcycle frame. When the measurements are the same, the front wheel
> should be straight ahead and vertical.
>
> Then I measure from the ends of the handlebars to a point in the
> center of the seat
> asfarback as possible. The measurements should be the same. Sometimes
> the throttle twist grip will be a little further to the right than the
> other grip is to the left. so I have to watch for that.
>
> If the bars aren't centered in the clamps, it's easy enough to loosen
> the clamps and center them, but be careful that the handlebar doesn't
> rotate forward or backwards, changing the angle of the control levers
> and the position of the mirrors.
>
>
>
> > My feeling is to go to the other shop (the one that did the original
> > MOT) and ask them for their opinion. At the moment I wouldn't feel
> > that confident doing it myself by eye.
>
> With a name like "Cori", I suppose you're female and not as
> mechanically-inclined as a man. Motorcycles are more of a hobby for a
> man who likes to tinker with his toys. The Japanese have tried to get
> the whole world onto motorcycles, but the mechanically disinclined
> person is going to be dissatisfied or absolutely angry with the $tealer
> $hips and their mechanic$ after a few visits.

No, am a 'bloke' as we say in UK - shortened version of real name I
use for texting, and preserves a little anonymity in the vast open
landscape of the web. Many 'Cori's are female though.

Appreciate the advice - don't have a centrestand so have yet to work
out a good way to prop the bike up for checking alignment etc. The
rear tyre of the virago is quite a bit wider than the front.

Took the bike out again today, and still feel something not quite
right, as if there is a 'drag' on the right bar, or a slight pull
which I have to counter with a slight push, or as if something just
isn't quite central, and looking down from the rider position when
going straight ahead (carefully as possible I might add), it looks to
me as if the clearances or gaps as they appear by eye between bars and
forks on both sides do not look the same. The gap and angle between
the horizontal of the bar to the left of the riser and the vertical
lower part of the fork looking different between the right and left,
with the larger gap on the left.

If it is just something like normal road camber feeling different
because the steering would have been stiffer and therefore less
sensitive before the repair, then I will look a bit of a pillock. I
would add also that I hate letting anyone else work on any vehicle
that belongs to me, and avoid it unless at all possible, so do have
pretty high standards and expectations.


Reply from: Morrgaine
Date: 27 Oct 2007, 19:26
Re: handlebar alignment

On Oct 27, 8:09?am, seabreeze <corrie...@yahoo,com > wrote:

>No, am a 'bloke' as we say in UK

OK, it's nice to know you're not totally nancy.

>Appreciate the advice - don't have a centrestand so have yet to work
out a good way to prop the bike up for checking alignment etc.

Got a shed or an off street place to work? Look for cinder blocks and
sturdy pieces of wood. We use old plastic milk crates for motocross
workstands.

A coffin hoist (come along) attached to a garage rafter works fine to
lift the front tire off the
floor and it's handier than a block and tackle. A telescoping carjack
works fine if you have to jack up the whole motorcycle from underneath
the engine. Or, you can use a cheap Chinese floor jack.

If you have to use a jack, be careful not to drop the machine.

Here in the USA, we can get a Chinese-built motocycle lift for
less than $100.

>The rear tyre of the virago is quite a bit wider than the front.

Yes, that's typical of a cruiser. But motorcycles have used different
sized tires on the front and rear since the 1960's. The rear tire is
larger to support more weight, give a better ride, and transmit more
power. The front tire is smaller for precise steering and it's just
big enough to do most of the stopping.

I tried to suggest that motorcycle use the same sized front and rear
tires to get more traction, but that notion has been thoroughly
discredited in favor of using a tiny front tire so a sportbike will
change directions quickly.


>Took the bike out again today, and still feel something not quite
right, as if there is a 'drag' on the right bar, or a slight pull
which I have to counter with a slight push, or as if something just
isn't quite central, and looking down from the rider position when
going straight ahead (carefully as possible I might add), it looks to
me as if the clearances or gaps as they appear by eye between bars
and
forks on both sides do not look the same. The gap and angle between
the horizontal of the bar to the left of the riser and the vertical
lower part of the fork looking different between the right and left,
with the larger gap on the left.

Since the steel stanchion tubes are just secured into the upper and
lower triple clamps by a single bolt in each clamp on that side, it's
possible for the stanchion tubes to be misaligned with each other. If
they are not parallel with each other at the triple clamps, they can
be misaligned 6 to 8 millimeters at the axle, so the front wheel is
never vertical at the same time the rear wheel is vertical.

When we would crash our dirtbikes, the front forks would be "tweaked"
in this manner, and we would jump up and grab the front wheel between
our knees and twist the handlebars until the front end was straight
enough to continue in the race.

We would wait until we got home to try to straighten everything
better, but, next time we crashed, the forks would get "tweaked"
again. The whole fork assembly on a motorcycle is just ridiculously
limber because of the way it's designed.

If you want to go through the disassembly and reassembly and rigging
of the
throttle and clutch, you can remove the controls from the handlebars
and remove the
handlebars from the motorcycle and lay them front side down on a flat
surface like a tabletop
and then you can measure with a ruler or tape to see if the ens of the
bars are the same dimension from the flat surface.

If this sounds too difficult, let me point out that I replaced my
first set of handlebars
with a bit of advice from a Honda mechanic about half an hour after I
bought the bike and immediately crashed it, not knowing how to ride.

I hate to sound like Robert Shapiro, but there are many possible
problems with motorcycle forks.
Telescopic forks are just a contraption grafted onto a motorcycle
frame, and motorcycles evolved from safety bicycles so the whole world
of motorcycles grew like a fungus and motorcycles make very little
sense to an engineer.

Another possible reason why motorcycle might pull to the right is that
the mechanic
didn't push the forks up and down several times before tightening the
axle pinch bolt
in the bottom of the left fork leg.

http :// demo.motorsportdealers,com /modules/oemparts/partsimage.gifx?t=20071027101142114TFS&z=2

The axle threads into a steel fitting in the bottom of the right fork
leg, and the mechanic is supposed to torque the axle, stroke the forks
to centralize the wheel and then tighten the
pinch bolt.

Another possility is that he didn't rock the front caliper to retract
the brake pads and
they pushed the front wheel and the bottom of the forks off to one
side. The caliper and disk are on the righ hand side of the front
wheel.

http :// demo.motorsportdealers,com /modules/oemparts/partsimage.gifx?t=20071027100928866NEM&z=2

If you have a place to work and you can support the weight of the
front end off the pavement, I recommend loosening the upper and lower
triple clamp bolts and loosening the axle pinch bolt and rotating the
steel fork tubes to see if anything moves.

http :// demo.motorsportdealers,com /modules/oemparts/partsimage.gifx?t=20071027101059021Y6B&z=2

If you rotate the steel stanchion tubes anticlockwise and the front
wheel moves side to side, you have a bent stanchion tube.

Also, if you rotate the front axle anticlockwise with the pinch bolt
loose and the front wheel wobbles and move up and down, the front axle
is bent.

>If it is just something like normal road camber feeling different
because the steering would have been stiffer and therefore less
sensitive before the repair, then I will look a bit of a pillock. I
would add also that I hate letting anyone else work on any vehicle
that belongs to me, and avoid it unless at all possible, so do have
pretty high standards and expectations.

I agree. I don't let anybody touch my bikes and when I go into a
motorcycle parts department, I often walk out without buying anything
because the $tealer$hips can't get a good parts counterman, let alone
a decent shop mechanic.

The parts countermen often cannot sell me the simplest parts because
they cannot find out what parts are interchangeable, even though the
same motorcycle may have been produced for 20 years.






Reply from: OH-
Date: 28 Oct 2007, 00:50
Re: handlebar alignment


"seabreeze" <corriequk@yahoo,com > wrote

> When collected and driven away the bars don't appear to be in
> a straight line when driving straight ahead - the right side slightly
> back and the left slightly forward.

and

> Took the bike out again today, and still feel something not quite
> right, as if there is a 'drag' on the right bar, or a slight pull
> which I have to counter with a slight push

If you want advice, I think you need to decide what the symptoms
are. This "guess what is wrong with my bike" thing is hard enough
as it is.

--
Ole Holmblad - Göteborgs Prima MCK / MK Pionjär
TDM850 / WR450F FL#44 OTC#489 UKRMSBC#08
SGFPTH#00 Remove hat to answer by mail




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