N28 Ground Valve Sleeves
These steel sleeves are used to straighten bent and out of round pistons. The sleeves have been bored and then honed to the exact sizes used when the valve casings were manufactured.
This is a forming die. They are not adjustable.
The recommended procedure for use:
• Remove the valve cap, finger button, stem and guide from the piston.
• Select the proper diameter sleeve and push the piston all the way in so the main body of the piston is completely covered by the sleeve.
• Hold this complete assembly in the palm of your hand.
• Use a F5 rawhide or F11 canvas mallet and strike the outside of the steel sleeve many times, rotating the sleeve in your hand as you go, so hammer blows strike the sleeve all the way around.
• Continue this procedure until the piston works freely in the sleeve.
SLEEVES ARE NOT ADJUSTABLE ORDER THE EXACT SIZE.
TO ORDER THE CORRECT SIZE—
Order by the O.D. of the piston. Example: Yamaha .664”. Due to the differences in manufacturing over the years it is highly RECOMMENDED to measure the valve piston.