Adjusting your ATV valves is important in maintaining peak performance and reliability. Though adjusting your valves is not difficult, is does require some patience and accuracy. On a single cylinder engine you have one set of intake valves and one set of exhaust valves. This will make for easy adjusting. When you’re adjusting a twin cylinder engine, there are two sets of exhaust and intake valves. The adjusting will be the same, just work on one cylinder at a time.
Before you start I recommend cleaning your ATV. Where we are going dirt is not allowed! Make sure you have a manual or know what your settings are. Take off your seat and remove any plastic needed to reach your valve covers. Once you reach your valve covers you will have to know which cover is your exhaust and intake. The easiest way of knowing the difference is that the exhaust valves will be located close to your exhaust pipe….hense the name exhaust. The intake valves will be located close to the carburetor or fuel injector. Again, hense the name intake because the motor must intake gas to run. Setting your valves sets the proper length of time to be open and closed while running.
I will be adjusting on a Honda Rincon single cylinder engine. Check your manual to see what the recommended clearance settings are for your ATV. My settings will be .006 on the intake valves and .013 on the exhaust when the motor is cold. After you take your valve covers off, your valves need to be in the proper position to adjust.
Exhaust valves: Slowly start to pull your pull start cord until your intake valves on that cylinder start to move up (starting to uncompress the spring). Once they slightly start to move up, Stop! This may take several times to get it positioned perfectly. Once it is in the proper position, check the exhaust valves clearance. It should have some clearance in there already. Set it to your manuals specifications. If your ATV was running fine and you have no clearance something bad is wrong and you should start over. Make sure you are on the correct set of valves.
Intake Valves: Again slowly start to pull your pull start cord until you see your exhaust valves just start to go down (starting to compress the spring). Once in the perfect position, check your intake clearance. Set it to your manuals specifications. The same rule applies for the intake valves. If it was running fine and you have no clearance, do not adjust the valves. Start over and make sure you are looking at the correctt valves.
• When the intake valve starts to move up check your exhaust!
• When your exhaust starts to move down check your intake!
Note: Be sure to double check after all of the adjustments have been made.