I wasn't getting true boiling on my OHV when the sides were out of balance but I was getting enough heat to get a little predetonation in the intake. Mine was
I should have added that if it is lean the plug will be whiteish near the tip. If it is too rich it will be black and trust me they do foul. I've had bad
I've got my OHV at about 140 degrees on both sides at the exhaust nut with a handheld scanning thermometer. I'm trying to decide if it's too rich or not.