Slipping in trans

[SuperCyclone.81]

I have at 2007 Genuine Rattler 110cc and I just replaced the gears on it yesterday. I was riding it earlier today and noticed that the trans isn't as "tight" feeling as it was before the gears broke. I had the trans all taken apart and sitting out for a little less than a month before I got the parts and got it put back together. Can you guys think of any reasons why it may not be bitting like it was when I took it apart? Thanks