2000 blaster with pro circuit pipe and silencer,oil block off, boyseen reeds,reed spacer,260 jet and kn air filter. stock carb other than jetting. stock needle position.
piston just froze up. i had it bored .020 and new wiseco piston.i tried a 280 jet for break in purposes and figuring new power from fresh engine and it wouldnt clear out so i put the 260 in and just taking it easy and it locked up while riding slow in sixth gear. im 300 feet above sea level(raleigh north carolina) what should it be jetted and is two thousands enough piston clearance? i also mixed klotts oil strong at 6 oz to a gallon plus added two ounces to first tank and didnt dog it. whats wrong? compression was 145 and 135 after locking up. now it is in the machine shop getting honed and ordering new piston. help please?

 

What color was the plug insulator? Was it running lean? Never mix extra oil in for break-in...it will just defeat the purpose of breaking in the new bore by adding extra lube.

 

That compression you gave is real high. Have you had any head work done to the motor? Stock compression is 127 psi. There is something off inside the motor if compression is really 145psi stock. After a new rebuild check it and if it is still that high you better find out why or you are just wasting money putting in pistons. My 99 is two summers old now and still on first piston and compression is still strong at around 127 psi.