ZeroClient wrote:
It looks like the top ring may have rotated past the locator pins? Take the bottom ring off the piston and push it into the cylinder. Measure ring-end-gap and post back.
Also measure your current piston-to-cylinder wall clearance. I'd say if the clearance is <8thou you might get away with a new piston and just a hone, but is doubtful. Think about your piston costs, hone costs, and consider going to 90mm. BTW on a CR500 sleeve you should be able to get all the way out to 91mm on Wiseco. that's a lot of bores/years.
Finally on your O-Rings. This one is easy.
The inner O-Ring you should use measure the diameter of the slot on the dome, and the thickness of the slot. You can refer to various sized O-Rings at
http://www.mcmaster.com. You want to be very careful with your selection however, because with the heat I would highly suggest you get Viton O-Rings for chemical and temperature resistance. Look here:
https://www.mcmaster.com/viton-fluoroelastomer-o-ringsThe outer O-Ring is going to be EASY. Either you can try to lay it out and measure the diameter, ordering O-Rings 3 times, which isn't a bad idea... OR, McMaster sells O-Ring cord stock where you can make your own O-Rings. Look here:
https://www.mcmaster.com/viton-fluoroelastomer-o-ringsAll you need is the diameter, and then cut the O_Ring to length. I'd use Permatex Water Pump and Thermostat RTV at the joining end to attach the O-Ring back onto itself. Clean cut the ends with a razor blade. Hell; I'd use that stuff to dress the entire O-Ring honestly. Let it dry for a few days before coolant is added. This is how we do it with large 2-cylinder JetSki heads with the outer o-ring.
Back from vacation and starting to get back to working on this .The outer ring on the dome does not look like a O-ring it is flat, while the inner ring is still round like an O- ring,Does this matter? HAs the outer ring just flattened over time? Also,it is measuring 2mm wide in its flattened condition,what size should I order? Inner o ring is measuring 2.6 mm
They both look like they are reusable, although the outer ring did have a small break in it.
I am guessing when I order gaskets I need to order two base gaskets, because I need to go ahead and replace the one on the bottom of the plate also?
I am still looking for someone to work on the cylinder