racerone, I've ckd the gear oil. It was clean and it took about 1 oz. to top it off. The starter pinion and spring look fine, and seem to move as designed.
Here's my compression checks ( I don;t know the number system of the cyls, so it's listed port upper, port lower, starb. upper, starb lower):
COLD: 90, 110, 130, 115. Second COLD test with different comp gauge: 110, 110, 125, 115.
HOT: 110, 115, 125, 125. Second HOT test with different comp gaige: 105, 110, 120, 120.
I used 2 different compression gauges to make sure the readings were somewhat similar.
Ran on the muffs with cowlinf off and still could slightly hear the sound at 3000rpm but exhaust noise mostly covered it up, and of course, there wasn't any real load on the motor.
I forgot to mention that I also replace the rectifier/regulator at the same time as the water pump. Required removal of the flywheel, which I did with a harmonic balancer puller without too much effort. Retorqued the flywheel to 105 ft. lb. Flywheel looks to be running true w/out any wobble or anything like that. I think I'll remove the flywheel tomorrow and double check for anything amiss there.
Do you think it could be a rod bearing getting ready to puke?
Any other suggestions or ideas would be appreciated.