Racing & Performance Tips
Results achieved by these tips are the sole responsibility
of the racer.
Question on Mikuni carbs ... The standard main
jet number for the kz900 is #110. Kawasaki show in the exploded view, five
different main jet sizes from 110 to 120. I know Vance & Hines Sidewinder
recommends installing #130 main jets before installing there 4 into 1 exhaust.
I think this just prevents the pipes from bluing / fine tuning. What's the
difference is my question? Does the main jet size give more fuel to the
carbs? The number means how big the hole is in the jet .. its
a measurement ... so yes the bigger the number the more gas it can flow
and yes it helps stops the pipes from bluing, bluing is from the motor running
too lean (not enough gas for the air going through it) lean = hot very lean
= melting pistons the richer it is the cooler it burns until you have so
much fuel in it your not burning it off then you get black smoke out the
pipes. So white smoke would mean a very lean mixture? White
like a fog is either anti-freeze or ATF being burned, nothing else burns
white, now there are different shades of blue.. from a grayish to navy blue..
the richer the blue the fresher the oil is that's being burned like rings,
light blue.. I would say valve seals gray to black is gas not being burned.
Head GasketsOn motors using 10.5 to 1 compression ratio pistons, a fiber
head gasket will work fine. For racing applications; where 13.5 to 1 compression
ratio pistons are used, a copper head gasket is required. Also, when using
a copper gasket, the cylinder block must be o-ringed to help the copper
gasket seal. Cutting a groove around the sleeve and using a copper wire
thickness of .039 is common place. Leave about .009 height of wire above
the block surface.
*A Note Of Caution:
When using fiber head gaskets, put them on dry; no sealers or coatings.
For copper head gaskets, a spraying of copper coat on both sides is sufficient.
Allow it to dry and tack-up for 2 hours before installing. Make sure both
the head and cylinder surfaces have been machined flat and are clean before
installing the gaskets.
Do not use a Copper Head Gasket on a water-cooled motor.
If the cylinder has been o-ringed, the gasket will not seal enough by biting
into the wire and the water will leak by causing overheating problems. Use
a spring steel head gasket and do not o-ring the cylinder.
Piston To Valve ClearanceFor those of you with a GSXR 1100, this is the easiest method:
Put a degree wheel on crank, get exhaust at 8 degrees BTDC. Set dial indicator
on valve tip and put screwdriver between the rocker arm and cam. Pull down
read indicator in thousandths to check clearance. With intake set at 8 degrees
ATDC, do same as above.
Ignition SystemFor those of you who plan to purchase the new Dyna-2000 ignition
for a GPZ 1100 motor (1981-85), you must use the ignition housing with seal
from a KZ1000J motor.
IgnitionsIf you are having problems with your ignition or rev-limiter
check your ground. Make sure that you are grounding to bare metal, not a
painted surface. Dyna Ignitions, rev-limiters, two steps and Dyna 4000 Ignitions
require the use of Dyna wires to work properly These wires have a wire spiral
core center which doesn?t interfere with the electronics on your bike.
When using a Vance & Hines PowerPak Ignition on your
sport bike, use 3 OHM coils with graphite suppression wires. With a Dyna-2000
Ignition, use 2.2 OHM coils with the same type of wire.
Ignition TimingWhen running a motor at high altitude you must advance the ignition
Example: a Suzuki GS 1100/1150 motor running at 4000 feet above sea level
would advance the ignition timing approximately 3-4 degrees.
Spark Plug GapsWhen running a Suzuki or Kawasaki with a Dyna-S and high performance
coils set plug gap at .026. When running an MSD or Dyna-4000 Ignition system
set plug gap at .018.
Spark PlugsRacing motors usually require a heat range one colder than stock.
We recommend NGK plugs. For a Suzuki GS1100-1150 use a D9EA. For a Kawasaki
KZ 900-1000 use a B9ES. With a Dyna-S ignition and aftermarket coils run
a gap of .028. If your vehicle has a MSD box or Dyna 4000 ignition run a
plug gap of .018 - .020.
Turbo Engine TimingTurbo bikes under boost create a tremendous intake charge. In
order to release this charge the exhaust must stay open longer than usual.
Suzuki and Kawasaki engines benefit greatly when exhaust cams are set at
112 degrees lobe centers. Set ignition timing at 28 degrees.
Nitrous OxideWhen running NOS on your bike use a gasoline with an octane rating
of 116-120. The higher the octane the slower the fuel burns. This allows
you to run a high compression without fear of pre-ignition and detonation.
The higher the compression the smaller you go on NOS and gas jet sizes.
If you have a low compression motor the bigger you can go on NOS and gas
jet sizes. Ignition timing must be set at 28? on Kawasaki KZ and Suzuki
GS motors. A rule of thumb in jetting is to allow a spread of 4 jet sizes
between gas and NOS, with gas being the larger of the two sizes.
Battery ChargingWhen using a total loss ignition system where the charging system
has been removed the battery only takes 1-2 runs to lose its peak voltage.
Re-charging battery between rounds with a 5 amp charger will cure this problem.
ManifoldsFor those of you who are planning on running 40mm Mikuni Radial
Slide carbs on your '91-92' GSXR-1100 motors, use the intake manifolds from
a 1988-89 GSXR-750 and match these to your intake ports.
Connecting RodsWhen installing Carillo rods on most late model sport bikes,
you need around .002 clearance on the big end of the rod. You need to use
Plasti-Gauge to determine how much clearance you have, then contact a dealer
about bearing sizes needed.
HorsepowerThe formula for figuring correct horsepower is RPM x Torque divided
If you are using a car tire chassis with your Kawasaki
motor, it is a good idea to have a heavy-duty 2nd gear input installed in
your transmission. In a high-horsepower motor there is a tremendous load
put on this gear when going into 2nd gear, because of the traction the tire
Most racing engine applications use an octane rating
of 108-114 when compression ratios of 12 to 1 or higher are used.
On turbo/nitrous applications where compression ratios of 8 or 9 to 1 are
common, an octane rating of 120 should be used. The higher the octane rating,
the slower the fuel is burned. This helps overcome detonation and pre-ignition
when large amounts of turbo-boost increase cylinder pressures causing heat
If you want more bottom-end torque, advance your intake
cam by 2 degrees.
For those of you running high-lift cams, .485-.507 lift
Kawasaki and .410-.420 lift Suzuki, we recommend changing your complete
set of valve springs every 15 passes for maximum performance.
If you are having problems with busted clutch plates
in your motor, Check the steel plates to see if they are warped. Clutch
plates need to be mated properly in order to get a proper grip and not distort.
CarburetorsFor those of you running 29 smoothbores on a mildly modified
street machine, here are some suggestions for carb modifications to give
better mid-range performance: # 20 Pilot Jets
# 0-4 Needle Jet
# 1.0 Air Jets
# 2.5 Needle & Set
* Float level heights, base of gasket to top of float 23.5 - 24.5mm
RingsWhen breaking in a new motor DO NOT use synthetic motor oil as
rings will not seal properly. Only use petroleum based motor oil.
Kaw Lock UpFor those of you setting up your Kawasaki lock up clutch: spring
pressure should be checked at .930? in a spring checker. You should look
for around 40lbs per spring.
CamshaftsAnyone building a CBR 600 F2/F3 motor for formula car autocross
competition with a turbo charger may benefit by using a set of California
EPA cams for these engines. With added boost from a turbo you don?t need
as much lift and duration in the cam. The EPA California cams are .220 duration
compared to the .235 duration 49 state cams of the regular CBR 600F2/F3
models. These are factory OEM camshafts. NOTE: California cams only have
.263 lift compared to .325 lift for the 49 state cams.
PistonsWhen cutting the domes of blank pistons cores you must leave
a minimum of .150 piston dome thickness for aspirated motors and .300 for
turbo charged applications.
ValvesWhen doing a street/strip port job on a GSXR-1100 water cooled
head we have found it very beneficial to go to a 1mm oversize intake valve.
NOSBefore filling that NOS bottle make sure it?s good and cold.
Place bottle for several hours in your freezer at home. NOS is under pressure
at about 200 degrees below zero. Getting the bottle cold allows it to pack
more tightly by creating a denser atmosphere. MAKE SURE BOTTLE STAYS COLD
UNTIL YOU GET IT FILLED.
Exhaust PipesTired of that new chrome exhaust system turning blue after a
couple of passes? Paint the inside of megaphone and head pipes with header
paint like VHT, etc. The heat is reflected off the coating and out of the
exhaust system. Heat does not get absorbed as quickly through the pipe wall.
Chain AlignmentA neat little trick to get your chain properly aligned on the
sprocket. Measure from center of swing arm pivot bolt to center of rear
axle. Make adjustments to either side to get them exactly the same.
Front End StiffnessDon?t run too high an air pressure in your front tire. 30-35
lbs is satisfactory. Keep front end springs on medium stiffness. Not following
these steps can cause the rear tire to lose traction at high end due to
unloading of chassis.
Heavy Duty Cylinder StudsWhen installing studs in cases put a drop of red Lock Tite on
threads and torque to 10-12 ft lbs.
Suzuki 750 Straight Cut GearsAnyone installing these gears in their motor will need to take
approximately 7 teeth off the rear wheel sprocket.
Intake ManifoldsAnyone planning on building a 1978 GS 1000 2V Suzuki and doing
a semi-pro ported head with 38 mm Lectron carbs, use Mikuni manifolds Part
#VM 36 -200.
Valve SealsFinding it hard to install seals on late model GSXR heads with
valve tappets? Applying a little white lithium grease to an 8mm socket will
hold seal on socket, then press firmly and evenly into place.
Air Kill / Rev LimiterWhen wiring a two-step with an air shifter on your bike you need
to wire the air kill to wherever the tach source is (i.e. Dyna-4000 MSD
box) so as not to interrupt the two-step.
Valve Spring PressureWhen checking valve spring pressure on your Kawasaki KZ900/1000
or Suzuki GS1100/1150, measure the seat pressure at 1.400? in a valve spring
checker. Kawasaki 90-100 lb, Suzuki 55-60 lb.
Valve Spring PressureGS1100/1150 48-50 LB Street GS110/1150 55-60 LB Street
Cylinder HeadWhen installing a GPZ head on a KZ-1000 Kawasaki bottom end you
must install a cam conversion tower. If the crank has a 15 tooth sprocket
use a 122 link cam chain and KZ 900/1000 cam sprockets (30 teeth). If the
crank has a 16 tooth sprocket use a 124 link cam chain and Kawasaki MK II
cam sprockets (32 teeth).
Wristpin ButtonsA method for determining what size teflon wristpin button you
need is to subtract the length of the wristpin from the bore size. Subtract
.020 from this figure, then divide by 2.
CrankshaftWhen using a GPZ crankshaft in your drag motor you should replace
the thrust bearing which is susceptible to failure with a needle bearing.
Crank will have to be disassembled. At this time it is a good idea to also
have your crank index trued and welded.
AirboxWhen running a full body and fairing combination on your drag
bike it is essential that you install an air box. The air is streamlined
around your fairing causing a dead air space in the area of your carburetors.
This starves your carbs of air and performance is dramatically decreased
as much as three tenths or more. Lining your air box with a heat reflecting
material will keep engine heat out so that you have clean cool air.
Street TiresFor you street racing fans here?s a hot tip for the stickiest
tire that?s DOT approved. Yokahama makes two compounds of this tire - either
a D-003 or D-006. Check your local dealers for a size that may be compatible
with your bike.
Intake ManifoldsWhen mounting Lectrons on your Suzuki GS1100/1150 use Dayco Radiator
hose cut to 1-5/8? length. For 40mm Lectrons use 1-5/8? I.D. hose, for 44mm
Lectrons use 1-3/4? I.D. hose.
Oil LevelWhen changing oil in your drag racing motor never exceed 2-1/2
- 3 quarts. This amount allows adequate lubrication while allowing minimum
crank windage. Break in new motors with good grade petroleum base 30w motor
oil. We recommend a 5w-30 synthetic motor oil either Mobil 1 or Torco at
Wheelie BarsIn setting up your wheelie bars we recommend painting your wheels
with white shoe polish. After making a run check wheels to see if both are
having weight applied equally. Adjust wheelie bar heim joints to compensate.
Fuel PressureIf you?re having trouble figuring out correct fuel pressure on
your turbo bike buy yourself a 16oz ratio-rite cup like the one moto-crossers
use for pre-mixing fuel. Disconnect fuel line going to carb and place in
ratio-rite cup. Turn on fuel pump switch and spin motor over with ignition
off. Cup should fill in Approx. 15 seconds. If not, adjust fuel pressure
regulator in either direction until result is obtained.
Mikuni 33mm SmoothboresFor those of you who still own these carburetors a little jetting
trick. In order to get better throttle response install 0.6 air correction
jets. This allows you to run a smaller main jet while still giving you approximately
the same air fuel ratio as before. Good starting point is 4 main jet sizes
smaller than you previously had. Also installing a O-6 needle jet will help
lean out the mid range.
Master LinkA good way to keep that master link clip from coming off of your
chain is to apply a small amount of clear silicone over the clip and let
SlicksWorn and dried drag slicks can come back to life with a paint
brush and a can of VHT traction compound available at your local speed shop.
Apply a few coats and let dry.
CoolingUse a portable fan hooked up to your generator to cool your motor
down between rounds.
OilingTo get maximum lubrication to your GS1100/1150 motor, remove
stock oil pump gears and replace with gears from a GS 750 4 valve model.
Camshaft LiftA simple method of determining the lift of your camshaft. With
a vernier caliper measure from heel of cam to nose, then subtract the base
circle. This gives total valve lift.
Tire Temperature/PressureA little trick that will keep your tires at a constant temperature
and pressure. Keep a nitrogen bottle with adapter and filler hose hook-up
in your van. Filling tires to recommended pressure with nitrogen keeps tires
from growing on hot days. Better foot-print maintained means consistent
times while keeping chassis from unloading due to traction loss.
Head Gasket SealingProper sealing of head gasket can be accomplished following these
1. Have your cylinder o-ringed
2. Treat both sides of copper head gasket with a light film of Copper Coat,
let dry for 2-3 hours
3. Torque stock cylinder studs to 36 ft lb., heavy duty cylinder studs to
42 ft lb..
Note: both head and cylinder surfaces must be parallel.
Piston to valve clearance ( minimum ): KZ / Z1 - 0.050 Int., 0.075 Ex.
GS 1100/1150 - 0.050 Int., 0.075 Ex.
Valve to valve clearance ( measured on the seat ):
KZ / Z1 - .200
GS 1100/1150 - .100
Cam Timing: KZ 900/1000, GS1100/1150
naturally aspirated motors 110 both intake and exhaust.
GSXR (stock cam) - 105 both intake and exhaust
GSXR (G21X cam) - 106 intake, 108 exhaust.
Use Kaw "J" model manifolds for mounting Lectrons
or Mikuni RS carbs on your KZ/Z1.
Use 1-3/4" radiator hose for mounting Lectrons
on your Suzuki GS1100/1150.
Lectron carbs set needle height adjustment
at 1.825 - 1.835.
Valve spring seat pressure:
KZ / Z1 / GPZ - 100lb
GS1100/1150 - 55-60lb
Standard lock-up clutch
use O.E.M. Clutch Springs
Kaw KZ 900 / 1000 / GPZ
Single plug head - 38 degrees
Dual plug Head - 32 - 34 degrees
NOS motors - 26 - 28 degrees
Suz GS 1100 / 1150
Single plug head - 34degrees
Dual plug (2-valve) - 32 - 34degrees
NOS motors - 26 - 28degrees
Heavy-duty cylinder studs torque to 40-42
Heavy duty main studs torque to 20 ft lb.
Largest valves on a stock seat:
GS 1100/1150 - 28.5mm Int, 24mm Ex
GSXR 1100 - 30mm Int, 26mm Ex
KZ 900/1000 - 37.5 Int, 31mm Ex
KZ 1000J/GPZ - 38.6 Int, 33mm Ex
To Degree Cams: Install degree wheel and find
TDC with a positive stop. Setup dial indicator on valve and zero indicator
with valve closed. Rotate engine until valve is .050" off seat and write
down reading on degree wheel. Continue to rotate engine until valve is .050"
from closing. Note the number.
To figure lobe center for intake cam subtract opening
number from closing number, divide difference by two and add that number
to 90. For the exhaust subtract the closing number from the opening number
and follow the same formula.
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