How to shim your carb needlles/ adjust mixture screws on your SRAD GSXR with carbs (96-97
750, 97-00 600)

This is for people with slip on exhausts and KN airfilters who do not plan to purchase a jet kit.
With your new high flow exhaust canister and (or) K&N airfilter your bike will become even more lean (not
enough fuel) worse than it was from the factory. From the factory many of our bikes are set just a little
lean to help pass emission tests. With a new pipes some power can actually be lost since the mixture becomes too lean. This mod can
also be done to a stock bike to help with throttle response in the mid range.

So here we go.

First thing to need to do is lift the tank and remove the airbox and drain the carbs. If you don't
know how, this is explained here. (spark plugs don't need to be removed).
Airbox removal:
http://www.gixxer.com/ubbthreads/showflat.php?Cat=&Number=849689&page=0&view=collap
sed&sb=5&o=&fpart=1
Carb draining:
http://www.gixxer.com/ubbthreads/showflat.php?Cat=&Number=849458&page=0&view=collap
sed&sb=5&o=&fpart=1


So the first thing we are going to do is shim the needles. The way the needle works basically is it
plugs a hole that fuel flows through. As the needle is raised out of the hole it allows more fuel to
be burned, as its dropped it slows fuel. In our case we want to raise the needle to "add" fuel...
thus shim the needle. The shims are .5mm and you can get them from dynojet.com or
factorpro.com or from a hardware store.
Shimming the needles affects the mid range (approx 4500-8500rpm)

First thing you need to do is remove the "carburator piston valve cover" It's the black plastic cap
on the front of the carbs. I suggest you work on one carb at a time for the needles. Each cap has
two screws, remove them.

http://www.factory8.com/r6msgnet/uploaded/Pistonvalveneedlecover.JPG


Next pull the cap off and remove the large spring, it pulls right out. Set the cap aside, upside
down. Put the two screws and the spring in it, so you don't misplace them.

http://www.factory8.com/r6msgnet/uploaded/Pistonvalvecoverremoved.JPG

Next pull out the entire rubber assembly you have just exposed. This is called the piston valve, it
holds the needle.

http://www.factory8.com/r6msgnet/uploaded/Pistonneedleassemblyremoved.JPG


You now want to remove the needle from this assembly. Looking down inside the hole that the
spring was in you can see a white plug. Grab it with some needlenose pliers and pull straight out.
Do so very gently, since when your pull out you will be exposing a tiny spring, you don't want to
lose it.

http://www.factory8.com/r6msgnet/uploaded/removeneedle.JPG



Now with the white cap removed flip the assembly upside down and the needle will come out
with some spacers on it (possibly the spring too if it didn't come out with the white cap). Note
the order of the spacers, you don't want to mix that up.
http://www.factory8.com/r6msgnet/uploaded/needleretainer.JPG

http://www.factory8.com/r6msgnet/uploaded/needle.JPG


Next what you will do is put a tiny shim, or washer on the bottom of the needle. Put in on from
the point tip and slide it up to the other spacers.

You now are ready to put it all back together. The only tricky part is putting the white cap back
on. You need to make sure the spring is seated on the top of the needle, and that you don't push
the white cap in too hard. I suggest you put a small socket on the white cap and give it some
light taps with something to seat it in the clips. NOTE: if you push too hard and break one of the
ams that holds the white cap it will cost you $50 for a new piston valve!. So just snug it down in
with some light taps.

http://www.factory8.com/r6msgnet/uploaded/longsocketinhole.JPG





Once you have the needle seated, check to make sure it springs a little inside the holder.
http://www.factory8.com/r6msgnet/uploaded/checkspring.JPG



Finally you are ready to put the parts back into the carburator. Make sure you line the needle up
and feed it in the hole on the carb all the way.
http://www.factory8.com/r6msgnet/uploaded/needleinhole.JPG



Once you have it all screwed back on nice, check to make sure everything is sealed good and it
make a slight suction sound. Pull font to back on the piston valve, it slides inside the carb.
http://www.factory8.com/r6msgnet/uploaded/checksucking.JPG
Do each of the four carbs the same way. (Should take approx 20 minutes).

Now for setting your mixture screws. You need to pop the carbs up off the motor to do this.
There is a small hole on each side of the bike. Put your screwdriver in the hole and find the
screw that holds the manifold clamps on the carbs. Just unscrew it about 6-8 turns, don't remove
it.
http://www.factory8.com/r6msgnet/uploaded/removecarb.JPG




Now you want to pop "UP" on the carbs. They may take a good tug. Check for wires and hoses,
you may have to remove one or two. If you do, label them so you know what is what.


You will see four little aluminum plugs on your carbs. You need to remove these plugs. I
suggest you drill a tiny hole in the plug, and then hand screw a tiny screw into that hole and tug
the cap out. It comes out rather easy you will see! Make sure you cover the motor intake while
you do this so you don't get aluminum inside. With the cap removed you will now be able to
see the brass mixture screw. I suggest for a KN and slip on exhaust you only go ½ extra turn out,
or counterclockwise. This will give you a little more fuel down low in the rpms. Mixture screws control the low end and idle. So you may have to readjust your idle once done.

And thats it! Do each carb the same way, button everything back up in revers order and enjoy
your bike. It should pull smoother and have a good amount of increased power in the mid range.

What all do you have to buy to do what your talking about and how much will I spend doing this?

When you take the cap off watch out for the small 4mm? o-ring that seals the carb to the cap for a small vent hole. They are easy to loose and are needed for it to operate properly. Great post!