Sounds like you have a slightly modified banshee. Do yourself a favor. DO NOT ride this bike until you have some type of air filter protection installed.
I would also recommend you check jetting as mentioned earlier. As for second gear issue. Your description of the issue doesn't match 2nd gear problems.
* Clean the bike until it looks good , then clean it some more
* pull the carbs to clean and check jetting
* Fresh fluids all around
* Fresh gas with quality premix
I've attached a picture of my bike when I bought it 8 month ago. Just a little inspiration for ya
Now post some pictures or we'll rip your arms off and shove them up your ass.
Troy