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Need help with the small oring that are for the coolhead


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There should be no need for any head gasket. It is there because some one was either lost, or they were looking for more squish and went about it in the most hillbilly way ever. Either way get it out of there!

 

The little o rings will go between the main shell and that top plate. So mount the domes and big main shell. Then put those little o rings on each stud and seat them in the grooves on the main shell. Last, put the top plate on.

 

Make sure to do a squish test to see what the clearance between the piston and dome is. If it's less then .045 which is possible if you get rid of that head gasket, you'll need to have the domes cut a touch deeper.

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So we're clear, that's a pro design head correct?

 

Squish test is simple. It can be done a couple different ways. Most precice way will be to cut a piece of flux core solder that is about an inch longer then the bore is wide. Bend the solder so that it is straight over each side of the wrist pin with the excess bent forward toward the exhaust side of the cylinder. Place the head on and torque it down. Roll the kick starter over till it smushes the solder. Measure it on the ends where the solder was in the bore edge where the piston meets the dome.

 

Or the most basic way. Cut 4 pieces of flux core solder about 3 to 4 inches long. Bend them in an L shape so once the head is on, you can put it in through the spark plug hole. When you do it you check left to right over the wrist pin. Not forward and back as the piston rocks that way. So one piece through the spark plug to the left and roll the kicker over with your hand till the solder smushes. Then repeat to the right over the wrist pin. Do the same in the other cylinder.

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Ok i gotcha i will have to get a measuring mic tho measure the flux.if there isn't enough clearance if i have 23mm domes should i go to 24s

No, the clearance will need to be machined. Just changing dome volume is affecting the big bowl area in the center of the dome and part of the flat angled cut. Are those just off the shelf Pro Design domes? If so they will be marked with a PD then whatever number. That number will be your CC volume.
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