The bike is an 82 Kawie KZ550 - C3, and I'm contemplating some
suspension work. The obvious work would include the installation of
new spring/shocks and rebuilding the forks.

Before I begin I am wondering if the repairs are really needed at this
time. Are there specific, objective tests of these components that
say "go" or "no go"?

Or are decisions made by "If it feels worn out it is"?

I do have a toolbox, a Clymer manual, and a positive mental attitude.
So tell me, Fount of All Knowledge, what are the objective means or
methods to test these components?

Thanks in advance,

Biker Dude.

Biker Dude <(E-Mail Removed)> wrote:

> The bike is an 82 Kawie KZ550 - C3, and I'm contemplating some
> suspension work. The obvious work would include the installation of
> new spring/shocks and rebuilding the forks.
>
> Before I begin I am wondering if the repairs are really needed at this
> time. Are there specific, objective tests of these components that
> say "go" or "no go"?
>
> Or are decisions made by "If it feels worn out it is"?
>
> I do have a toolbox, a Clymer manual, and a positive mental attitude.
> So tell me, Fount of All Knowledge, what are the objective means or
> methods to test these components?
>
Objective testing would require all sorts of measuring apparatus and
kit.

You'd need to measure the springs against factory length as new, measure
the spring rate against factory spec, etc etc ad infinitum.

Just assume that on a bike that's nearly 30 years old, and which was
built with crude suspension in the first place, that the shocks are
knackered and the forks probably worn out too.

Mileage helps here - under, say, 20k miles, you might be tempted to
leave things alone and only replace if you can feel (for example) a
bouncy rear end and soggy forks.

Over 30k miles and still on the OE shocks? Throw them away and take it
as read the front will need attention too.

Rear shocks are dead easy to sort - unbolt old units, throw away, bolt
on any decent branded pattern that fits.

Forks: I'd start with some quality pattern springs, a fork oil change -
the manual will give the right viscosity - and maybe new seals. All
pretty simple stuff, and cheap too.

Remember that, like I said, you're dealing with an old bike with a very
old-style chassis. There's not much you can do to make it handle like
something more modern. But a simple rear shock change and a fork rebuild
will definitely help. I wouldn't bother getting more ambitious than
that.



--
BMW K1100LT Ducati 750SS Honda CB400F Triumph Street Triple
Suzuki TS250ER GN250 Damn, back to six bikes!
Try Googling before asking a damn silly question.
chateau dot murray at idnet dot com

The Older Gentleman wrote:
> Biker Dude <(E-Mail Removed)> wrote:
>
>> The bike is an 82 Kawie KZ550 - C3, and I'm contemplating some
>> suspension work. The obvious work would include the installation of
>> new spring/shocks and rebuilding the forks.
>>
>> Before I begin I am wondering if the repairs are really needed at this
>> time. Are there specific, objective tests of these components that
>> say "go" or "no go"?
>>
>> Or are decisions made by "If it feels worn out it is"?
>>
>> I do have a toolbox, a Clymer manual, and a positive mental attitude.
>> So tell me, Fount of All Knowledge, what are the objective means or
>> methods to test these components?
>>
> Objective testing would require all sorts of measuring apparatus and
> kit.
>
> You'd need to measure the springs against factory length as new, measure
> the spring rate against factory spec, etc etc ad infinitum.
>
> Just assume that on a bike that's nearly 30 years old, and which was
> built with crude suspension in the first place, that the shocks are
> knackered and the forks probably worn out too.
>
> Mileage helps here - under, say, 20k miles, you might be tempted to
> leave things alone and only replace if you can feel (for example) a
> bouncy rear end and soggy forks.
>
> Over 30k miles and still on the OE shocks? Throw them away and take it
> as read the front will need attention too.
>
> Rear shocks are dead easy to sort - unbolt old units, throw away, bolt
> on any decent branded pattern that fits.
>
> Forks: I'd start with some quality pattern springs, a fork oil change -
> the manual will give the right viscosity - and maybe new seals. All
> pretty simple stuff, and cheap too.
>
> Remember that, like I said, you're dealing with an old bike with a very
> old-style chassis. There's not much you can do to make it handle like
> something more modern. But a simple rear shock change and a fork rebuild
> will definitely help. I wouldn't bother getting more ambitious than
> that.
>
>
>

From the shop manuals I've seen, usually the only spring check is
length. That's pretty easy. Rear shocks wobble and bounce when they
are shot, especially on turns, that's pretty easy to check too.
Standing on the pegs and leaning on the front shocks is pretty easy as
well, just compare with how a new showroom bike feels. Some old-style
forks need a special bit to undo, not sure about Kawasaki, but with some
filing you can make the square tip for many Suzukis from a larger hex
socket bit. Putting new front seals in isn't hard but needs care and
gentleness to put them in square and there's no point if there are a lot
of scratches or corrosion. One or two little scratches usually don't
matter. Pretty important to make sure both have the same amount of fork
oil Straightening front forks isn't hard but it's best done with an
H-press and a true table, maybe even a dial gauge. However a straight
edge is good enough for making sure they aren't bent more than 1/8" or
so over two or three feet.


Any little grit can work its way into rubber and ruin fork stems. I
know quite a few riders who clean chains religiously but never wipe down
their fork tubes!

paul c wrote:
....

Forgot to mention one trick I've seen but is not mentioned in all shop
manuals - before removing front stems, try to loosen the bottom bolt on
traditional forks, ie. before unclamping from the tree, might save
having to put them in a vice or using a impact wrench or driver to get
those old bolts undone.

paul c wrote:
> paul c wrote:
> ...
>
> Forgot to mention one trick I've seen but is not mentioned in all shop
> manuals - before removing front stems, try to loosen the bottom bolt on
> traditional forks, ie. before unclamping from the tree, might save
> having to put them in a vice or using a impact wrench or driver to get
> those old bolts undone.

Everything might go well as it has a few times for me, except that a
couple of times I forgot to have a pan and some rags handy when I
unfastened the tube, pointing down and spilled oil on the floor. Even a
few hundred ml's of fork oil makes a nasty mess.

paul c wrote:
> paul c wrote:
>> paul c wrote:
>> ...
>>
>> Forgot to mention one trick I've seen but is not mentioned in all shop
>> manuals - before removing front stems, try to loosen the bottom bolt
>> on traditional forks, ie. before unclamping from the tree, might save
>> having to put them in a vice or using a impact wrench or driver to get
>> those old bolts undone.
>
> Everything might go well as it has a few times for me, except that a
> couple of times I forgot to have a pan and some rags handy when I
> unfastened the tube, pointing down and spilled oil on the floor. Even a
> few hundred ml's of fork oil makes a nasty mess.

Sorry for all the posts, I keep remembering things from a few years ago
- it's really important to make sure you either have a very good memory
or take photos or have a good parts explosion diagram, because there are
some little parts, round on one dimension but asymmetrical on another,
inside the front fork assemblies, whose orientation can be very easy to
get wrong when re-assembling. A casual glance might suggest washers or
whatever they're called are the same from two different manufacturers,
but they really aren't.

paul c wrote:
....
> Sorry for all the posts, I keep remembering things from a few years ago
> - it's really important to make sure you either have a very good memory
> or take photos or have a good parts explosion diagram, because there are
> some little parts, round on one dimension but asymmetrical on another,
> inside the front fork assemblies, whose orientation can be very easy to
> get wrong when re-assembling. A casual glance might suggest washers or
> whatever they're called are the same from two different manufacturers,
> but they really aren't.

Eg., A friend had a tech school rebuild his shocks. One leaked, so I
put new seals in it but when dis-assembling thought something wasn't
right, looker closer but couldn't figure out whether one of the inside
bits was upside-down or not. Looked at the other shock and it was
reversed. The microfiche at the dealer was no help, the resolution just
wasn't good enough. Half a dozen mechanics looked at it and couldn't
decide either. That's when I decided it was just as well to do my own
work. I still don't know if I got them put in right, just made sure
both forks were the same and haven't heard of any problems since, and
there were no more leaks. In that case (CB750) I sandpapered a short
piece of ABS plastic drain pipe to press the seals in with. Coated the
seals with oil to make that smoother.

paul c wrote:
....

Another one about paying attention during dis-assembly, some springs are
graduated, usually but I'm not sure if always, there are more turns per
length at the top end. The upper parts are meant to handle the smaller
bumps. I've seen more than one shop mechanic put springs on upside
down, likewise putting drain holes on turn signals point up into the
downcoming rain. In part, I like two-wheelers because they are so much
simpler than other kinds, it's still amazing how many people can screw
them up.

On Feb 25, 12:44*pm, Biker Dude <jacobsenpa...@hotmail.com> wrote:

> Before I begin I am wondering if the repairs are really needed at this
> time. *Are there specific, objective tests of these components that
> say "go" or "no go"?

It's hard to tell if the springs are sacked out without a lot of
diasembly and measurement, but there are ways that experienced riders
use to tell if the springs are strong enough to do their job.

Find out what the stroke of the front forks is so you'll have an idea
of how saggy the front springs are.

Place a ty-wrap (zip tie) around the steel leg and take as much weight
as posible off the front end with one hand and push the ty-wrap all
the way down onto the dust seal.

Then gently sit down on the bike and get off and measure how far the
ty-wrap moved. If it moved more than around 50% of the stroke, the
springs are too weak *for your weight."

You can do the same test on the rear springs, which have adjustable
preload.

You should use up about 33% of the stroke just sitting down on the
seat. If you use more than that, the springs are either too weak *for
your weight*, or they are
sacked out.

So far as the rebound damping of the shocks and forks is concerned, do
the wheels chatter when you go across bumps?

That means the rebound damping is inadequate, possibly because the oil
in the dampers is too thin or too old or there just isn't enough oil
there.

And, if you are going around a fast curve with the motorcycle leaned
over to 40~45 degrees and the chassis starts misbehaving and the
motorcycle starts heading over the center line, that's a pretty good
indication that you don't have enough rebound damping, for one of the
reasons in the previous paragraph.

Here's another oddball one - use a magic marker to to note where the
tube and stem line up before you take them apart. I met some mechanics
who do the same when undoing axle nuts and claim that avoids a torque
wrench on re-assembly, but I don't know if they're right about that.