Instruction manual

COPY
-3-
Dec./08/’06
◇ Loosen the nuts / washers and bolts on the
cylinder head in a few steps in the following
order as shown in the figure below.
●Removal of Cylinder Head, Cylinder,
and Piston
◇Remove two dowel pins and a cam chain guide.
If you find no wear or damage upon checking,
reuse them.
◇ Remove the cylider and two dowel pins. If you
find no wear or damage upon checking, reuse
them.
◇ Remove wrist pin circlips, pull out a wrist pin,
and remove the piston.
※Plug the opening on the crank case with a
waste cloth not to get any foreign material in it.
◇ Completely get rid of the gasket scraps
remaining on the mating surface to the cylinder
with a scraper or the like.
◇ Remove the waste cloth plugged in the
opening.
◇Check, through the cam chain hole, whether
the cam chain has not come off the sprocket on
the crank shaft.
◇Degrease the mating surfaces of the crank case
and the cylinder with thinner or the like, and fix
dowel pins and cylinder gasket included in the
kit.
◇ Fit the cylinder into the piston little by little with
fingers, being careful not to shift the piston ring’s
end gaps out of the position, and then fit the
cylinder into the crank case.
※When the piston is fitted into the cylinder, pass
the cam chain through the cylinder.
◇ Degrease the upper surface of the cylinder,
and fix two dowel pins and a kit’s cylinder head
gasket. Fit the cam chain guide precisely to the
groove on the cylinder.
●Cylinder Installation
◇ Fix piston rings to the piston. Letters “1R” and
“2R” are engraved on the top and second rings
respectively. Be sure to fix the rings so the
sides with the engraves letters face upwards.
※Be careful not to damage the piston or break
the rings.
◇ Apply engine oil to kit’s wrist pins, pin hole on
the piston, and to an end on a connecting rod.
Fix the piston to the connecting rod with the
arrow on the top of the piston facing the
exhaust side, and then fix the wrist pin circlips
included in the kit.
◇ Apply engine oil to the piston rings, and make
sure than the rings turn smoothly.
１
２
３
４
５
６
◇ Remove the bolt and stopper plate.
●Change of camshaft
(in the case of a cam being provided.)
Adjust nut
◇ Detach the rocker arm shafts both on intake and
exhaust sides with a sliding hammer.
Special tool to use: Sliding hammer
Yamaha-made genuine tools:
・Balancer shaft puller bolt: (90890-01085)
・Weight: (90890-01084)
◇ Attach a bolt of the cam sprocket to the
camshaft, and pull out the camshaft from the
cylinder head.
※ Never pull it out forcibly.
◇Turn the cam toward the combustion chamber,
and install the rocker arm and stopper plate.
◇ Apply engine oil to the cam on the provided
camshaft and to the bearing, and install the bolt,
and install the camshaft to the cylider head.
◇Install a wrist pin circlip to one of the pin holes on
the piston.
※Attach the piston pin circlip so the ring end gap
does not meet with the notch on the piston pin
hole, and ring end gap should be either on the top
or at the bottom of the hole as illustrated in the
figure below.
● Piston Installation
Letter
Top ring
Letter
Second ring
Expander
Side rails
Wrist pin’s direction
Piston
Right angle of the wrist pin
◇ Remove a tappet cover and O-ring both for
intake and exhaust, and loosen the adjust nut
and adjust screw on the rocker arm.
Stopper
plate
Sliding hammer
Apply oil here.
Apply oil here.
Circlip
Notch
End gap