How to Set the Valves on a Kawasaki Bayou 300by Chris Gilliland
Kawasaki's Bayou 300 ATV is powered by a single-cylinder, two-valve engine. During normal operation, a set of rocker arms push down on the valves, allowing fuel to enter while forcing exhaust gases out. The valves do not directly touch the rocker arms until the moment they are pushed downward, creating an air gap or clearance between the valve stem and the rocker arm. During the course of the ATV's lifetime, the force generated by internal combustion forces the valves upward, reducing the valve clearance. However, proper valve clearance is maintained through the use of threaded adjusters built into the rocker arms.
Park the ATV on a level surface surface and apply the parking brake. Let the engine cool for at least two hours.
Remove the seat using the release lever under the left side of the seat. Unbolt the front carrier rack and the front brush guard from the ATV using a 12 mm socket and a socket wrench.
Remove the screws from the lower fuel tank cover using a Phillips-head screwdriver. Push the cover up then away from the ATV. Remove the screws attaching the sides of the front fender to the foot well panels using a Phillips-head screwdriver. Remove the front fender mounting bolts using a 10 mm socket and a Phillips-head screwdriver. Unscrew the gas cap, then lift the front fender off the ATV.
Screw the gasp cap onto the fuel tank. Turn the fuel tank valve, located under the left side of the tank, to the "Off" position. Pull the fuel hose off the valve outlet using pliers. Unscrew the mounting bolt from the base of the fuel tank using a 12 mm socket. Lift the fuel tank off the ATV.
Remove the valve adjuster cap, located on the front and rear of the engine cylinder head using a 10 mm socket. Remove the guard plate from the left engine cover using a 10 mm socket.
Unscrew the timing inspection port cover and the alternator access cover, located at the front and center of the left engine cover, respectively, using a flat-head screwdriver.
Place a 17 mm socket and a socket wrench over the now-exposed alternator bolt. Turn the alternator counterclockwise and watch the intake valve located at the rear of the engine cylinder head. Stop turning the alternator once the valve opens then closes. Turn the alternator again until a "T" is visible near the notch cut into the side of the timing inspection port.
Slip a feeler gauge between the intake valve stem, located at the top of the valve, and the rocker arm. Ideally, there should be a 0.003- to 0.005-inch air gap between the valve stem and the rocker arm. Additionally, the feeler gauge should be able to move between the valve and the rocker arm with a slight drag.
Loosen the adjuster locknut on the top of the rocker arm using an 8 mm box-end wrench. Turn the adjuster clockwise using a flat-head screwdriver to decrease the air gap, or counterclockwise to increase the air gap. Measure the air gap again and make adjustments as needed. Hold the adjuster in place with the screwdriver, then tighten the adjuster locknut when the intake valve clearance air gap has been set to 0.003 to 0.005 inch. Skip this step if the intake valve clearance was correct.
Check the air gap between the exhaust valve located on the front of the engine cylinder head and its accompanying rocker arm. Ideally, the exhaust valve has an air gap measurement of 0.005 to 0.007 inch. Adjust the exhaust valve clearance as described in the previous step, if needed.
Screw the timing and alternator inspection port covers into place, then reinstall the left engine cover guard plate. Tighten the plate bolts to 7.6 foot-pounds using a torque wrench. Reinstall the valve adjuster covers onto the engine cylinder head. Tighten the cover bolts to 7.6 foot-pounds.
Reinstall the fuel tank onto the ATV. Push the fuel hose onto the fuel tank valve outlet. Reinstall the front fender, lower fuel tank cover, seat, front carrier rack and front brush guard onto the ATV.
- A ticking sound coming from the valves while the engine is running could be caused by a loose camshaft chain. The chain controls the valve timing and is regulated by a self-adjusting chain tensioner at the base of the engine cylinder. This tensioner normally does not need adjustment; however, a sticking or malfunctioning tensioner could prevent the chain from being held under tension, allowing it to rattle against the cylinder. In these cases, the tensioner usually can be removed, cleaned and reset.
- Do not check or adjust your Bayou 300's valves if the ATV has been ridden within two hours of beginning the task. The engine must be completely cold in order to obtain accurate valve clearance measurements.