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KX 80 siezed and scored piston.

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Hey gents......have a look at this and give me some ideas. I will have to do some more research on the matter. There are suspected radiator cooling issues. The cooling fins may not be getting enough air through them and the carb may not be correct. The run in fuel mix was 20:1. The standard recommeded mix for normal conditions and riding is 32:1. The plug is a B9ES. The main jet is a 122 and the pilot is a 55. The air screw was out 1.5 turns. It would stop as if is siezed at high RPM. I did not check the fuel level height but I did check the float height. 


Any thoughts or input while I do some investigation here. Oh and the plug is a tan colour.....not black or oil fouled. But it was oil fouled at one stage. 


I pressure tested the engine before installation and there were no leaks.




Any comments would be great. 


Kind regards 

Edited by GEOF

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I would think the main should be closer to the 140 range....but I dont know what needle. Sorry I have not read you entire thread...but too me you had rubbing issues the way that piston is pushed down on the rings. Looks like the PV was rubbing it. I know the piston is toast but is the jug scored or just marked up? What kinda surface does it  have? Plated or sleeved?

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