Steve Gold of APS Shows
how He Prepares His GPR for Racing.
GPR 1200 Super Stock
2001 Yamaha GPR 1200 Super
To prepare for the Upcoming Season
to give the GPR a thorough going
First the motor is removed and
a complete tear
down and cleaning is done on
Tapping and Heli-Coil fresh Stainless
into the case assembly &
intake mounting surface were done .
Getting the Crankshaft To
Phil @ Crank Works was next where a complete rebuild was done using New
Yamaha OE 1200 Rods with SKF Bearings over the O.E. Koyo brand that were
on the crankshaft,
I have seen the MAG side bearing
failure on several GPR motors so for additional Lubrication Phil added
a second oiling hole that was machined into the SKF front bearing and matched
to weep hole in the upper case half.
Then the crankshaft is trued
up & rod pins welded.
Prior to installing the Crank and re-assembling
the bottom end a quick check on how true it was.
Less then 0.001 of Deflection is a Beautiful Thing
Next the Crankcases are cleaned again and prepped
for assembly, New O.E. crank seals are installed with a thin bead of Three-Bond
1211 sealant around the case halves, a small dab of Stud & Bearing
Loc is applied to each of the main bearings and PJ1 assembly lube is lightly
applied to the Connecting Rod bearings then Crank Cases are torqued to
Prepping the Cylinders was next Using Kawasaki
82.25mm PRO-X Pistons.
The cylinders were honed out using a Sunnen precision
Hone to achieve exact clearance on each of the cylinders. Then I chamfered
the ports and washed them up for assembly.
Then the Cylinders / Power Valve Assemblies &
Heads were installed with New O-Rings, Gaskets and a light coat of Assembly
Lube and Torque to OE Specs. With the Starter Drive installed the Coupler
and Flywheel are also Torqued down .
Before final assembly of the front cover I re-checked
the pick up trigger clearance using a dab of clay and MSD trigger shims
to set the gap between 0.070 & 0.080 clearance.
Black RTV Silicone and small tie-downs work excellent
to insure that the wiring behind the flywheel stays in place during operation.
After everything is set in place the front cover O-ring
is installed and torqued down .
The NOVI 48MM Carbs were gone over too, complete
tear down & cleaning with fresh Diaphragms,
Needle Valve Assemblies, Needle O-rings & Gaskets.
Then the Pop-Off Pressure is Matched for each Carburetor.
After Inspection of the Reed Cages I decided to
Replace the Pedals using replacement Reeds from Lillian @ Rius Racing
Fresh Fuel & Water Lines were installed then
the Engine is placed into the hull and shimmed for Drive Line Alignment,
The Coupler Shaft had recently had new bearings so that step was skipped.
The Terminal ends on the battery cables were replaced and New Ground Wires
to the MSD Coils were put in.
The Triple pipes were installed with new O-Rings
/ Lord Mounts / Clamps & H-D Springs
Setting up the Magnum E+ Setback Pump was next
with Fresh OE Bearings and Seals and a Re-Pitched Prop from Dave @ IMPROS
the Preparation of the GPR was near complete
Finally Done ! As you can see very Sano in here.
Once the Re-Assembly was done some minor adjustments to the
BULLETT HANDLING PACKAGE & Steering system were done and a trip to
the lake for some testing and dialing...... AHHH Can't wait for the Season
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