sputter

Well I just bought my first bike and it's likes to sputter in the upper gears. And in 5th gear it will hardly go 80 without the rpm hand jumping around. Any ideas what it could be? Thought I might have junk in the carb.? What's ur thoughts?

Hello wide world of bike enthusiasts. I have a small problem I was hoping I could find the solution to. I have a 1978 Honda xl175 that I've owned for about 10 years. It has been one of the most reliable bikes let alone one of the most fun. The bike has 4100 original miles, and everything else on...