Hey everybody. 1975 cb550. Last spring I tore down the engine. New piston rings, cylinder, rocker cover, and all associated gaskets and o rings, etc. Rode great all summer. Today I changed the oil, drained and put in fresh gas, took the fully charged battery off the trickle charger and connected it back to the bike, and put air in the tires. Should fire up and go, right? Wrong.
It started up with one push on the electric start, but it was making some serious pinging noise from inside the engine. I gave it a little throttle and it turned off. Now it seems to be seized. The kick won't kick. Hitting the electric start I can here the starter spin but the engine just hits a wall and won't budge. It rolls in neutral and it rolls in first gear. It won't shift any higher than first gear. The crankshaft bolt only turns about 20 degrees in either direction.
So. What the hell? Cam chain tensioner no good? Cam chain came off sprocket some how? What was the loud pinging noise? Valves were fine last time I rode it. Stuck pistons? Just changed oil so it wasn't lubricated enough when I started it? Or, something I haven't gotten into at all yet, transmission problem? Really disappointed. After all that work last year I thought I was just gonna charge the battery and go. Any help is greatly appreciated.