Upgraded from the GZer to the VZer ?'s

[JTF]

So I sold the GZ in the spring, and after several months of not riding I HAD to get a new bike. I moved up a size to the VZ800. I had a few questions and thought maybe someone here could help even though it's for the 800 and not the 250... i found a lot of helpful knowledge on here when I had the GZ!

I changed the spark plugs (which was quiet a chore for the first time), and saw that the back cylinder spark looked good, but the front cylinder spark was black and fouled up. The exhaust on the front cylinder has quite a bit more coloration (blueing) on it, and when I started it back up, a bit of smoke was produced from the front cylinder's exhaust but not the back.

So being a complete motorcycle novice, and only having driven a single cylinder, I am unsure if it's normal for the cylinder's to run very differently, and not sure what would be causing it. For now it's seeming to run better with the new plugs, and I put in a bit of Seafoam. Any thoughts/suggestions are appreciated. Thanks!