How Do I Adjust My Valves?
Adjusting the valves on a scooter is not an easy task, nor should it be completed without the proper tools or experience. For those who feel comfortable with this job, you'll probably know that each manufacturer has specific rules and guidelines on valve lash (clearance) and how they should be set. Noted below is a basic instructional list of steps that you should complete when adjusting the valves of a scooter purchased through Killer Motorsports. If you have any hesitation on completing this job 100% accurately, please STOP and have an experienced mechanic complete valve adjustment as needed.
First, a few indicators on when valves should be adjusted. When a valve's clearance from the rocker arm and valve stem is too large, the valve doesn't open up fully (and you'll probably hear a clicking or knocking sound). Conversely, if the valve lash is too tight, the valve won't close or open fully or correctly, leading to poor engine performance and in some cases, compression or exhaust issues that can cause major mechanical damage. For those who feel comfortable moving forward, noted below are a few important steps to follow about adjusting valves on a scooter motor.
- Always Adjust Valves Cold: A common rule in setting valve clearance is making sure that the engine is cold. If the engine valve is adjusted when hot, it will close or loosen when the engine is cold and vice versa.
- Place Scooter on a stand for stability and security
- Take valve cover off
- Find TDC: Place a wrench on the nut that attaches to the fan (if there is one) or the crank and rotate the engine until you reach Top Dead Center. If you look at the flywheel of a scooter motor, sometimes TDC will be marked with an "X" or "T" or they will be indicated on the outside of a cam-sprocket .
- Adjust Intake and Exhaust Valves: Once you're cylinder is at TDC, you can adjust the valves. It's always a good idea to start with intake and then finish with exhaust. Contact your engine manufacturer to receive the correct valve lash settings for intake valves and exhaust as most likely they will be unique and different per each scooter manufacturer. Again, you should know how to adjust valves if you're trying this on your own, so we won't get into the specifics about this process.
Adjusting valves should only be completed after contacting the sales and technical team at Killer Motorsports to ensure any warranties or other issues are handled appropriately. Our technical team can help you with the proper valve adjustment settings and also help you find a local mechanic that is certified to work on your specific brand of scooter if needed.