Originally Posted by graphiteman
I have a a VZ-R that I just replaced the piston/sleeve in (never started), and with the plug out, it has just a light pinch at TDC just as you describe. My other VZ-R has several gallons through it, and it has seen 280 F a few times..... still runs excellent. I think its just starting to break in, you have nothing to worry about.
Do these motors have con rod problems? we had two 1/8 onroad racers loose rods, both engines were new, both on there 15 to 20 tanks, the rods broke above the crank pin. I have never seen a rod do this. the one motor is junk, rod went out the bottom and toasted the sleeve also.