Adjusting valves on these motorcycles is effected by replacing shims situated between the rocker and the top of the valve stem. It is not a job for the impatient. It can also turn out to be quite expensive as shims sell for around $10 and there are 8 of them.
Remove the seat,fuel tank and air cleaner assemblies.
Once you have the valve covers off you will need to measure the valve clearance. This is done by inserting a feeler guage between the valve and rocker arm when the particular cam lobe for the valve is pointed away from the rocker arm. Refer to the diagram. Measure at points 1 and 2 when the cam lobe is pointed away from point 3. Do this by inserting consecutively thicker blades into the space until a slght resistance is felt when moving the blade into and out of the space.
Record the measurement for each of the valves by rotating the engine each time to get the cam lobe pointed correctly.
Compare these values to the manufacturers specs.
Intake : 0.10 to 0.15mm (0.004 to 0.006 inches)
Exhaust : 0.20 to 0.25mm (0.008 to 0.010 inches)
If the measurements are out of spec you will need to replace shims for the affected valves.
Remove the camcaps by removing the bolts in a criss-cross pattern. Do not disassemble them as this is not nescesary if you only need to replace shims. Do not remove or disturb the heads or you will need new headgaskets. If you are going to re-use a shim it needs to go back on top of the valve where it was removed from. Do not turn the engine with the camcaps removed. Remove only on camcap at a time.
Remove the shim for a particular valve and measure its thickness. Use a micrometer as a most verniers are not accurate enough.
Subtract the highest manufacturers value for a particular valve clearance from the actual measured value. Add this value to the measured value of the shim for that valve. This is the minimum thickness of the shim needed. You may find that that exact number might not be available, so take the next thicker size available.
Measured clearance value for an exhaust valve = 0.29mm
Measured value of the shim for that valve = 2.69mm
Minimum shim size needed : 0.29mm-0.25mm+2.69mm = 2.73mm
So 2.73mm is the smallest size needed to get back to spec. However this will put you at the largest allowable clearance and a couple miles down the road you will need to replace the shim again as it will have worn down out of spec.
Calculate the largest size shim needed for that valve.
Maximum shim size needed: 0.29mm-0.20mm+2.69mm=2.78mm
It would therefore be best to take the 2.75mm shim to get the clearance back in spec.
On reassembly note that the locating dowels for the cam caps are refitted. Retighten the cam caps in a criss-cross pattern.