I have heard of people using solder to measure this but cannot find a description of how to do it. This is what the pistons look like. I do not know if I am supposed to go around the flat edge or over the dome with the solder. Any guidance will be appreciated.

 

Crown clearance perhaps? Used to rebuild Deutz air cooled engines, diesels for underground mobile equipment. Would put a piece of solder in the glow plug hole and turn it over by hand then pull and mic the solder to make sure the clearance was within spec. Nowadays you would use plastigage, but a piece of solder still gets the job done. Don't know why you figure you need to do this on your bike?

Jim

 

I assume you are using those pistons with HTCC heads? If not, you are wasting your time. The motor will be a turd without the HTCC heads they were designed to run with. Those pistons have multiple squish bands. Solder on the flat edge of the piston at each side over the pin and solder over the hump to measure squish at that point. Personally, I would use clay but if you use solder, use .030"; just be careful when rolling the motor over and if it gets hard to roll over, back off. Check with head gasket in place and if .030" doesn't flatten, check again with .060". If running high lift cams or bigger valves, drop some clay or solder in the valve reliefs to check valve to piston clearance. I would also clean those pistons up before checking.

 

I only asked because I read that others had done it. I do have the htcc heads. I will use the clay. Thanks tho you both for your insight.
Yes, they will get a good cleaning before they go in the engine.

 

We have modified that piston dome, via machining them while held in custom soft-jaws in one of our lathes, and then, the head is mounted in a fixture, and in the same lathe, with the compound rest at the same degrees/angle, the chamber is then machined to match.
Scott

 

I would like to do that but my wife has put my addiction on hold for now. I will do the best I can with what is available to me now. The next step in the addiction would be stealing from her purse and pawning jewelry but I have not hit rock bottom yet. I will have to run it like this for now. I was thinking next Christmas time I could send my stuff to you Scott to go from a 95" to 98". That is the best I can do after getting cams put in and tuning on the dyno. I was thinking the Andrews 57h or 67h. I know the 57s have the power in 2200-5400 and 67s are 2600-6400. I think I am usually cruising between 2500-2800 but I have touched 6000 rpms a couple of times. Never the 6200 limit set right now. I am now sure if I am not using all of the range because it feels flat or I just want spend more time riding and building, not fixing.
Thanks for your in put.