Your Yamaha Maxim motorcycle has eight valves: four intake valves and four exhaust valves. The intake valves for the front and rear cylinders are opposite each other at the gap between the cylinders at mid-engine. The exhaust valves are located at the outer corners of each cylinder. A cam chain operates the valves, and the chain must be properly adjusted before the valve clearances are set. Adjust the valves on your Yamaha Maxim motorcycle while the engine is cold.
Park the motorcycle on the center stand or elevate the rear wheel off the floor using wood blocks under the lower frame tubes. Put the transmission in top gear.
Remove both spark plug wires by hand. Loosen and remove both spark plugs counterclockwise with a spark plug wrench or a deep socket and a ratchet.
Remove the cam chain adjustment cap on the back of the cylinders just below the carburetors, using an adjustable wrench. Look inside and identify the hollow adjuster stud with a hex head and lock nut. Notice the tip of a metal pin in the center of the hollow adjuster stud. This is the traveler pin that rides on the cam chain.
Rotate the rear wheel of the motorcycle forward by hand as you observe the tip of the traveler pin. It moves in and out as you rotate the rear wheel. The cam chain adjustment is correct when the pin moves the same distance each way.
Adjust the cam chain by loosening the lock nut at the base of the adjuster stud counterclockwise with a metric socket and a ratchet. Turn the adjuster stud clockwise or counterclockwise by hand as needed until the tip of the traveler pin moves equally each way you rotate the rear wheel forward. Tighten the lock nut clockwise once the cam chain is adjusted.
Thread the cam chain adjustment cap clockwise into place and tighten it with the adjustable wrench.
Remove the valve cover caps at the upper sides of the cylinders counterclockwise with the adjustable wrench.
Look inside the front opening at one side of the rear cylinder where a valve cap was removed. Notice the position of the rocker arm. The intake valve rocker arm must be fully up in order to adjust the intake valve. Rotate the rear wheel forward until the rocker arm is fully up and pauses for an instant before engaging again. Take the time to get this setting right.
Refer to your repair manual for valve clearance specifications, and select the appropriate feeler gauge. Insert the feeler gauge between the underside of the rocker arm and the top of the valve stem. The gauge should slide in and out with light resistance.
Adjust the valve by loosening the lock nut on the rocker arm stud with a metric socket and ratchet. Turn the rocker arm stud clockwise with a screwdriver if the clearance is loose, and counterclockwise if the clearance is tight. Tighten the rocker arm lock nut clockwise when the feeler gauge slides in and out with light resistance.
Repeat the valve adjustment procedure to adjust the remaining intake and exhaust valves. Make sure the rocker arm is fully up when you set that particular valve clearance. Tighten the lock nuts securely after each adjustment.
Thread the valve caps in place clockwise and tighten them with the adjustable wrench. Reinstall the spark plugs and tighten them clockwise with the plug wrench. Attach the plug wires to the spark plugs by hand.
Items you will need
- Service manual
- Spark plug wrench
- Metric sockets and ratchet
- Adjustable wrench
- Feeler gauge
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