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I used some freeze spray and a heat gun to help with the installation of the tapered steering head bearings and the custom bronze swingarm bushings. It seemed to help and worked pretty well!
Hey Jadus! I've been lurking on your build for a long while now. I actually picked up an SR250 for myself. It's in the process of being disassembled to see its condition. What size piston did you end up using?Once the cylinder was on it was possible to rotate the engine and check to see if the top ring gap was still in the position it is supposed to be - which is evident with a streak in the lightly oiled bore (red circled detail).
I got the head on with the copper gasket in between as well. I will button everything up with torque wrenches another day!
One thing I did not research so much about was the way in which a copper head gasket should be used. It is generally considered standard practice to 'oring' them around the bore. If you're not familiar with that, give it a quick google search, cool stuff. It ensures a gas tight compression seal. I did not do this and am hoping I won't need to - there are plenty of people that have successfully used copper head gaskets without oring-ing them. However, if I get head gasket failure when I run the engine, I will know why and will know what to do... It'll be 'off with 'er 'ead! A great advantage of this engines cylinder and head interface is the use of orings around the oil feed galleys - in contrast to many car engines which rely on the head gasket to seal oil and water passages as well. So there was no need to use silicone around those areas like some people suggest (for copper head gaskets in car engines).
Hey man, cool you got yourself an SR! The piston is 77mm which results in a 2mm cylinder liner wall (at it's thinnest section) and results in a 263cc engine with a compression ration of about 10:1 (when using the thinner copper head gasket).Hey Jadus! I've been lurking on your build for a long while now. I actually picked up an SR250 for myself. It's in the process of being disassembled to see its condition. What size piston did you end up using?
Not so worried but the engine will get both the oil cooler we developed and tested as well as finned valve and cam covers - all of which help dissipate a few degrees of heat from the oil over stock. We actually have one last oil cooler left for sale on our webshop if you are interested. This batch is the last batch we will ever have made.Are you worried about the heat when increasing the displacement and compression ratio? I imagine there's not much we can do to increase an air cooled engines cooling capacity