Harley sounds like a steam engine when running or like a compression release is open?

Question

It's a buddies bike. It sounds like compression being released or a steam engine when running. Then it will just stop for a while, then start up again. Nobody seems to know the problem. No loss of power, just a weird sound.

Answer 1

Check for leaks in exhaust or intake

Answer 2

Could be a blown head gasket. I'd check the crankcase breather, it could be kinked or plugged.

Answer 3

I would bet the farm that it's a head gasket.

Answer 4

buy new bike

Answer 5

does it have compression releases? look on right side of cylinders toward the top, it's not unusual for a piece of carbon or trash keep the release slightly open.

Answer 6

Maybe a loose spark plug but that wouldn't make sense that it only does it sometimes.