Engine and Transmission
Turbo Oil Leak sources
Hi all
Anyone in need of the main shaft seal for a Seca Turbo oil pump -
The seal is not listed by Yamaha as they only ever sold complete pumps which
are now obsolete.
I have managed to track down what appears to be an identical seal as used in
many Honda model oil pumps including the GL1800 Gold Wing.
The Honda part number is 91208-MN1-771 and the seal size is 11 x 15 x 3mm
If this seal has failed you will be getting oil flowing back to the turbo
Cylinder and Piston -- Inspection and Repair
F. Cylinder
1. Inspect the cylinder walls for scratches. If vertical scratches are evident, the cylinder wall should be rebored or the cylinder should be replaced.
2. Measure cylinder wall wear as shown. If wear is excessive, compression pressure will decrease. Rebore the cylinder wall and replace the piston and piston rings. Cylinder wear should be measured at three depths with a cylinder bore gauge. (See illustration.)
Cam Chain Adjustment
The cam chain becomes stretched with use, resulting in improper valve timing and engine noise. To prevent this, the cam chain ten-sioner must be adjusted regularly.
1. Remove the timing plate cover.
2. Slowly rotate the crankshaft counterclockwise until the "C" mark on the timing plate aligns with the stationary pointer.
Thermostat
REMOVAL AND DISASSEMBLY
1. Drain coolant
2. Remove horns 1
3. Disconnect electrical leads 2
Middle Gear -- Inspection and Repair
P. Middle Gear
1. Damper disassembly
NOTE:
Disassembly of the middle gear damper requires the damper compressor (special tool) and a hydraulic press.
a. Place the middle drive shaft in a press with the damper compressor (special tool) in place as shown.
Piston, Pickup Coil, Shifter, Starter, Generator and Clutch Removal
C. Piston
1. Mark each piston to aid in reassembly.
2. Place a clean towel or rag into the crank-case to keep circlips and material from falling into the engine.
3. Remove piston pin clips, piston pins, and pistons.
D. Pick-up Coil Assembly
Engine Removal
ENGINE REMOVAL
NOTE:
It is not necessary to remove the engine in order to remove the cylinder head, cylinder, or pistons.
A . Preparation for Removal
1 All dirt, mud, dust and foreign material should be thoroughly removed from the exterior of the engine before removal and disassembly. This will help prevent any harmful foreign material from getting into the engine oil.
Clutch and Shifter Reassembly
5. Clutch assembly
a. Install the thrust plate onto the transmission main axle.
1. Thrust plate
b. Install the oil pump drive sprocket onto the main axle without the spacer collar and place the oil pump drive chain on its sprocket.
1. Oil pump drive sprocket