Hi thank you for your question hope this helps.
Atune-up is general adjustment and maintenance
to ensure peak engine performance.
The following section discuss each phase of a
proper tune-up which should be performed in the
order given. Unless otherwise specified, the engine
should be thoroughly cool before any tune-up procedure
Have the new parts on hand before beginning.
Camshaft Chain Adjustment
The engine is equipped with an automatic camshaft
chain tensioner. No adjustment is required.
Valve Clearance Check and Adjustment
Valve clearance Intake and exhaust
0.15 mm (0.006 in.)
Check and adjust the valve clearance while the
engine is cold (below 35° C [95° F]).
1. Park the ATV on level ground and set the parking
2. Remove the recoil starter cover (Figure 58).
3. Remove the fuel tank and the engine heat guard
4. Remove the bolts and the cylinder head cover
(Figure 59) and gasket.
5. Remove the O-ring (Figure 60).
6. Remove the spark plug. This will make it easier
to turn the engine with the recoil starter and align
the timing marks.
Remove the timing hole cap (Figure 61).
8. The engine must be set to top dead center (TDC)
on its compression stroke for checking and adjusting
the valve clearance. Perform the following:
a. Pull the recoil starter handle slowly and align
the T mark on the flywheel with the index
mark on the rear crankcase cover (Figure 62).
b. Move both rocker arms by hand. When the
engine is set at TDC on its compression
stroke, both rocker arms will have some side
clearance, indicating that the intake and exhaust
valves are closed. If the rocker arms are
tight (indicating that the valves are open),
turn the crankshaft 360° and realign the T
mark as described in sub step a. The engine
should now be set at TDC on its compression
9. Check the clearance of both the intake valve and
exhaust valve by inserting a flat feeler gage between
the rocker arm pad and the valve stem (A,
Figure 63). See Table 9 for the intake and exhaust
valve clearances. When the clearance is correct,
there will be a slight resistance on the feeler gage
when it is inserted and withdrawn.
10. Adjust the valve clearance as follows:
a. Loosen the locknut (B, Figure 63) and turn
the adjuster (C) in or out until the clearance is
correct. There should be a slight resistance
felt when the feeler gage is drawn from between
the adjuster and valve tip.
b. Hold the adjuster to prevent it from turning
and tighten the locknut securely as shown in
c. Recheck the clearance to make sure the adjuster
did not move when the locknut was
tightened. If necessary, readjust the valve
11. Install the spark plug and spark plug cap.
Tighten the spark plug to 18 N•m (13 ft.-lb.).
12. Inspect the O-ring for cracks or other damage
and replace it if necessary.
13. Lubricate the O-ring with oil and install it into
the rocker arm holder groove (Figure 60).
14. Remove all gasket residue from the cylinder
head cover and cylinder head gasket surfaces. Replace
the cylinder head cover gasket if it is leaking
15. Install the cylinder head cover gasket.
16. Clean the cylinder head cover and oil passages
with solvent and compressed air.
17. Install the cylinder head cover (Figure 59) and
tighten the mounting bolts securely.
18. Install the timing hole cap and O-ring, and
tighten to 10 N•m (88 in.-lb.).
19. Install the engine heat guard and fuel tank
20. Install the recoil starter cover (Figure 58).
Hope this helps