These instructions start with the cylinder and head removed from the engine with the piston removed from the crank rod as well. A spare piston could be used as well.
Tools needed: feeler gauge set
1.Take the rings off of the piston making sure you know which one is the top ring and which is the 2nd ring (if you are checking your existing rings)
2.Take the rings and put them down in the cylinder about 3/4"-1". Use the piston top to help square up the rings on the bore.
3.You will need a set of feeler gauges to take this measurement. Something that looks like this.
4.The gap you are going to measure can be seen here.
5. Here is a couple of pictures showing how to measure this gap. You can measure with the feeler gauges at an angle or straight up and down. The important thing is to keep the feeler gauge perpendicular to the ring surface.
6. Start with around .011" feeler gauge and slide it between the gap. If it fits with "wiggle" room or very sloppy, go to the next size up. Continue to go up until you reach a size that will no longer fit. Then drop back down one and try it again very gently. If it still fits, then that is your ring gap number.
Additional Information:
According to Wiseco, the ring gap should be determined like this:
Top Ring - Bore size(in inches) X .004"
2nd Ring - Bore size(in inches) X .005"
Example - 310cc big bore kit is 72mm stock bore, so 72mm = 2.83inches, 2.83inches X .004 = .011 for top ring, 2.83 inches X .005 = .014 for 2nd ring
The Honda spec says anything from .011 -.020 is ok (atleast for top ring anyway). Anything more than that requires something to be changed.
