Do you have a temp gun? If not, go buy one yesterday. It will alleviate problems like this. But I think the others are spot on. I had the same problem when I first got my temp gun and started learning to tune my first ntiro. I had the shift point all messed up and it still wouldn't shift, and it turned out that it was just because it was out of tune. SO I tuned it properly and rest the sift point and never had a problem after that. The other guys are spot on with the tuning being a probable cause worth investigating. If I were you, I would reset the shift point to the factory setting, and reset the needles on the carb to factory settings. Once you get it started and get the motor warmed up, tune from there. If you tune before it warms up, your tune will be way off.
If you have any trouble, Rolex is one of our resident tuning experts, and he has an amazing ability to help you diagnose tuning problems over the internet, as well as tell you exactly what to adjust and how much.
