[net.cycle] Shims

schwager@uiucdcs.CS.UIUC.EDU (03/12/86)

.
Anybody have experience working on valves that use shims?  I'm thinking
of getting a Kawasaki KZ750 and the valve adjustment on those uses
shims.  But I don't want to have to bring it in to a dealership every
3000 or 6000 miles and pay them exorbitant amounts of money for a
little work.  So can the average joe do it?  If I have to keep $20
of spare shims around, no big deal.  I figure I'll make up the price
after just a couple of tune ups by saving on labor.  What's the straight
scoop?  Thanks for the help, as always!
-mike schwager
-- {ihnp4,convex,pur-ee}!uiucdcs!schwager   schwager%uiuc@csnet-relay.arpa
	University of Illinois, Dept. of Computer Science

jamitche@uok.UUCP (03/17/86)

Can't answer for Kawasaki but I'm real familiar with Honda shims
(I used to own a '81 CB900F)(before some CAR driver totalled
it for me) and yes, shims are no big deal, just a pain. Firstly, 
you don't know what shims you'll need till you've got the old 
ones out.(oh yeah, measure the valve/shim clearance beforehand,
in the method your manual says).The shim'll probably be numbered
somewhere. If not, you'll have to take a micrometer to it.
(don't be scared, a cheap mic costs $8.00 at a hardware store).
     You'll probably also need SPECIAL TOOLS to get to these
shims. If they're like honda's, you really do need the
special tools, too. 
    Here's a hint, make a map. Measure all the valves, take
'em all out, record their codes or thicknesses on the map. 
Then go down to the dealer. Keep the map. Next time you do
this, you can see how much they've worn. 

animal@ihlpa.UUCP (D. Starr) (03/17/86)

> 
> .
> Anybody have experience working on valves that use shims?  I'm thinking
> of getting a Kawasaki KZ750 and the valve adjustment on those uses
> shims.  But I don't want to have to bring it in to a dealership every
> 3000 or 6000 miles and pay them exorbitant amounts of money for a
> little work.  So can the average joe do it?  If I have to keep $20
> of spare shims around, no big deal.  I figure I'll make up the price
> after just a couple of tune ups by saving on labor.  What's the straight
> scoop?  Thanks for the help, as always!

Checking the valves is not all that difficult.  I'm not totally familiar with 
the KZ750 top end, but if it's like either the KZ900 I used to ride or the 
KZ650 I used to maintain for someone else, it's just time-consuming.  You
have to remove the gas tank (easy) and cam cover (many bolts but easy) and
gasket (difficult, but you only do it once--then you glue the new gasket to
the cover with weatherstrip cement and put silicone seal (easily separated
next time) on the other side) to get to the valves.  Then you just spin the
engine around (with the kickstarter or that big nut on the crankshaft) and
check the clearances when the valves are fully closed.  

The odds are that once you get out of initial break-in (say, 5000 miles)
the clearances will be fine.  These shim-type arrangements wear very slowly,
and I know lots of people who go 20000 miles before needing an adjustment.
So you may decide it's best at this point to check them yourself and go 
to the dealer for adjustments if you find them off.

If you decide to do the adjustment yourself, you'll probably have to remove
the camshafts (eight bolts each, and you need a torque wrench to reinstall).
There's a chance that the shims will be on top of the lifters, in which case
you can use a special tool to remove them without pulling the cams (is this
a 750 4-cylinder or the very non-current twin?), but I wouldn't bet on it.
The camshaft R&R's not all that difficult really, but there is a bit of work
needed to re-establish valve timing when you put them in (line up crank at
THIS mark, pull chain tight, line up one camshaft HERE and bolt it down, 
count so many links on the cam chain, line that up with THAT tooth on the
other cam, bolt it down and torque everything down in sequence).  By all
means get the FACTORY service manual for torque values, clearances and
timing marks.

In my experience with Kawasaki fours, the check takes about two hours the
first time and 45 minutes once you get the hang of it.  The adjustment
takes about half an hour more, not counting the trip to the dealer for
shims (and the trip to the other dealer when the first dealer you go to
doesn't have the one you need).  Add more time to this estimate if you've
got a lot of fiberglass junk surrouding the engine.

mazlack@ernie.berkeley.edu (Lawrence J. Mazlack) (03/21/86)

>> Anybody have experience working on valves that use shims?  I'm thinking
>> of getting a Kawasaki KZ750 and the valve adjustment on those uses
>> shims.  But I don't want to have to bring it in to a dealership every
>> 3000 or 6000 miles and pay them exorbitant amounts of money for a
>> little work.  So can the average joe do it?  If I have to keep $20
>> of spare shims around, no big deal.  I figure I'll make up the price
>> after just a couple of tune ups by saving on labor.  What's the straight
>> scoop?  Thanks for the help, as always!
>
>Checking the valves is not all that difficult.  I'm not totally familiar with 
> ...
>If you decide to do the adjustment yourself, you'll probably have to remove
>the camshafts (eight bolts each, and you need a torque wrench to reinstall).
> ...

I used to work on a shim adjustment engine and it is a pain.  Granted, CHECKING
to see if the tolerance is not too bad, once you take off enough stuff to get
at it - but, the adjustment process usually requires a fair amount of
knowledge, skill, and time. Also, you might need special tools. It is easier
to get a bike that doesn't use them.

Larry Mazlack
mazlack@ernie.berkeley.edu
 

struve@calma.UUCP (Dimetry Struve) (03/22/86)

I think the Kawasaki 750 (wasn't that the bike in the original article)
uses shims under the cam follower. This means the cams have to be removed
to replace the shims. This is more time-consuming than difficult. I was
very reluctant to try adjusting the valves on my CB900F, and had the dealer
do it a few times. The Honda has the shims on top of the tappets, and they
can be pried out with a screwdriver. When I finally decided to try the job
myself, I found that it's easier to check and set the clearances than it is
to get the tank, valve cover, etc. off to reach the cams. I also learned
that the last time the dealer had done it, they had screwed up. Needless to
say, I'll never trust them again. Incidentally, my bike has required about
four valves to be adjusted in almost 50k miles. The Kawasaki, with the
shims not in direct contact with the cam should last forever.
 

schwager@uiucdcs.CS.UIUC.EDU (03/24/86)

.
Thanks to all who responded to my shim question!  It didn't sound too
scary, so I went and bought the KZ750.  Once again, thanks much!!
-mike schwager
-- {ihnp4,convex,pur-ee}!uiucdcs!schwager   schwager%uiuc@csnet-relay.arpa
	University of Illinois, Dept. of Computer Science

john@pbpra.UUCP (John D. Carmichael) (03/25/86)

In article <8800034@uiucdcs> schwager@uiucdcs.CS.UIUC.EDU writes:
>
>.
>Anybody have experience working on valves that use shims?  I'm thinking
>of getting a Kawasaki KZ750 and the valve adjustment on those uses
>shims.
   
     I got fed up with dealer service on my Yamaha FJ1100 too.  Expensive
and shoddy for the most part.  I decided to adjust the valves myself,
although I'd never done it before.

	The toughest part (on my FJ) is getting all the little pieces off
so you can get to the valve covers. The tank is also a bear (next time
I'll make sure it's empty...it weighs a ton).  You should have the
mechanics manual on your bike,  as it will tell you where to position
the crank to measure the valve clearance and you need the lookup chart
for the shim sizes.  

	Tools/supplies required: screw driver, feeler guage, assorted wrenches,
special tool to hold down valves (see your dealer, cost ~$16), magnetic
probe to grab the shims, mechanics manual.  You may also need a new valve cover 
gasket (~$19 on my FJ, aayeeee!).  Shims at ~$4.00 (buy these last). 
Gasket sealer to keep oil from leaking.
	
	On my FJ there are 16 of the little mothers, but note 
that the shims for exhaust and intake are identical (they 
come in various sizes however).  For the most part,
these shims do not wear out.  The dealer even offered to take
my old ones in exchange for the new sizes I needed, but I didn't have
time to do the job in one day.

	You measure the present valve clearance (jot down the present
clearance , and if it's out of spec, you take out the shim.  There is 
a trick to taking out the shim that my manual didn't tell me. 
Before you tighten the special tool to hold down the valves, you 
rotate the shim and the gizmo it's seated in until a notch about 4mm wide 
by 2 mm deep is visible. Use a screw driver to rotate this (the cam 
lobe should not be contacting the shim, or it will be difficult to 
rotate). It is IMPORTANT to have this notch in position (as I found out), 
because otherwise it is virtually impossible to pry the shim out!

Once you have the shim out you look at the number on the bottom of 
the shim (states the thickness), and look in a chart in your mechanics
manual.  This chart will then tell you the size of the shim that should
go in there.  Do not rotate the cam shaft lobes onto the valves unless
a shim is present.

	From the factory, my FJ had several different size shims in it,
Since some of the shims that were the wrong size at one valve location
were also the right size for a different valve, I was able to swap
them around and avoid buying new ones.  This is why you measure everything
first and then go buy the shims you need.  It might be easier to
have a few extra at the start, since you can't take them all out and
rotate the camshaft. 

	Once you've got the new shims in, check the clearances again.
Occasionally, you'll have to get a slightly larger or smaller shim than
you originally estimated.  Save any left over shims for next time.

	When replacing the valve cover, I recommend some gasket
sealer on the rubber seals surrounding the mounting bolts.  This is
where most of the oil leaks from.  The actual valve cover doesn't
leak perceptibly.  The gasket should only have gasket sealer on one 
side (the side next to the cover).  I was able to reuse my 
gasket, so I'm stuck with an extra one...oh well.

	The end result: one weekend (1-3 hours for you experts),
one $16 tool, and two $4 shims later and everything works great!

	I had the dealer do the adustment at 600 miles ($105 on my FJ), 
but after that it's cheaper and more satisfying to do most work myself.
I do better work than they do anyway!




			John D. Carmichael, PacBell
			dual!ptsfa!pbmnms!john or dual!ptsfa!pbpra!john
			voice: (415)-823-2822