I wish that I could say it started right up and everything was ready to go, but nothing is ever that simple. After a full tear down and re-build of the 1981 Suzuki GS650 engine, it actually did start right up, but it wasn’t quite right. It was idling well and revving well, but the No. 2 exhaust was cold.
I checked the basics. Compression was previously checked, it had spark, and there was fuel in the float bowl of the No. 2 carburetor, but the fuel was not getting to the cylinder.
I checked the carb synchronization and idle pilot jet, but nothing was changing how it was running. Time to pull the carburetors back off and take a look.
It turns out that it has been more than 3 years since the engine was last running and even though I did a full cleaning and re-build of the carburetors at that time, the engine was not shut down properly after the broken rear cam chain guide. Classic signs of ethanol based fuel gone bad in the No. 2 carburetor. A green tint to the fuel and clogging of the main jet was evident.
Luckily, nothing had hardened in the passage ways so it was fairly quick to unclog and get back together again.
After confirming that fuel was able to flow through all of the correct areas, everything was put back together and a quick bench synchronization of the carburetors was done in case I had messed anything up with my previous adjustments on the bike.
Back on the bike again and it fired right back up again and appears to be running well on all cylinders. It sounded so good that I wanted to go for a ride, but I will check the carburetor vacuum synchronization one more time and then reinstall the fuel tank to be ready to go.