New bike owner, first post (main jet question)

[Ooates]

Hi there, I just bought a 2007 GZ250 about a week ago as my first bike, super excited to get into this hobby.

The couple I bought it from just had the carbs cleaned and rebuilt (they provided the receipt). The bike runs good, only 7k miles on it.

I bought this bike as a learner to get my feet wet and I know they’re not meant to be speed demons by any stretch, but I’m have trouble getting it to 50mph (I’m 6’1 180). And I know that’s too slow. At about 45 to 50mph when I’m at full throttle I’m getting hesitation/bogging. Not crazy amount, but I feel as if it’s something to do with the mixture being too lean.

So with my limited amount of mechanical know how I tore into the bike to try to diagnose the problem. First thing, front caliper was seized up. So I’m replacing those and that should help with some extra mph. The main thing I saw was a new K&N air filter put on by the guy who rebuilt the carb. Called the guy, he said they didn’t rejet the carbs after cleaning so it’s definitely running lean and he suggested I put the factory airbox back on.

From what I’ve read on here, putting those air boxes on can be a pain in the butt, and if I can get some extra power out of rejetting the carbs I feel as though I should buckle down and learn how to do it.

Any suggestions on what path I should take? The airbox was $180 and I bet if I took the bike in it’d only take a guy 2ish hours to rejet it and it’d be the same price. Or should I do it myself?

(I’m also planning on gearing up to give myself some more top end speed)