Ok guys, I am really needing help on this, I must be halfway slow. I bought this 1983 shadow vt500c with rear cylinder inoperable. Upon bringing it home, I drained the bowls to discover that the rear cylinder carburetor is carrying orange gasoline! So I had the carbs cleaned thoroughly and put fresh premium gas into the whole system. I then continued to reassemble the bike. To my dismay, the rear cylinder is not firing at all (or firing rarely, or firing slow, or firing some other way but correctly). I checked the coils by swapping them... no difference. Checked the resistance in the wires, it is ok. Replaced spark plugs with the manufacturer recommended NGK plugs, no difference. Tested the spark generators for ohms, checked out. Swapped the CDI on both sides with one another and then in every combination I could with a different one that I purchased, nothing! Furthermore, I checked compression, it is ok! The front cylinder just keeps starting right up and the thing sounds like a lawn mower!!! If anybody can think of anything I missed during my trouble shooting, let me know I am pulling my hair out!!