06/05/2024
Trouble-shooting a problem motor takes a lot of trial and error, and an extreme amount of patience!
Often you canāt see the problem until youāve pulled back far enough to look at the bigger pictureā¦
Iāve taken the past couple weeks trying to figure out an extremely problematic motor; an air cooled V-Twin that has been running hot, losing power under load, having massive positive pressure in the crankcase causing blow by up the dip stick tube, as well as gasoline blow by out of the carburetor, and making some crazy noises.
Upon removing the left bank rocker cover I found the intake valve rocker was not seated on the spring but rather, pushed sideways. None of the push rods were bent, but the piston head was badly scored and heavily caked in carbon deposits.
The entire head was burned thick with coked up gasoline, piston rings were distorted and stretched, and nothing was the way it needed to be inside the case.
I honed the cylinders, put new pistons and rings in, cleaned the heads entirely of carbon deposits, ensured the lifters were in good shape, cleaned out the valve tubes and ran the valves with a wire brush.
New head gaskets, new head bolts, all torqued to spec and reassembled.
Test drive the motor and as soon as it comes under load, no power and stalls out!
Tonight Iāve realized my mistakeā¦
Looking at the bigger picture, listing out all these issues and bringing it all together, I recognize that the one thing I didnāt do was check the valve stems were not bent! š¤¦
A bent valve stem will prevent the valve from seating properly, which will cause overheating, poor performance, loss of power, gasoline blow by from the carburetor, positive pressure in the crank case etc etc!
Iām excited to get this sorted, because although mechanical work can be frustrating, it in itself is entirely void of emotionā¦ it is ultimate cascading logic - āif this, then that!ā, and Iām not going to allow myself to be beaten by a machine!
I may have dealt with all of the symptoms, but tonight it dawned on me what the root cause of those symptoms, what the āif thisā¦ā is, and thatās a beautiful thing. š¤
