In between studying for some IT exams at work, I finally got the top off my carb again, which would be vastly easier if the seat, side panels, tank, throttle cables, and choke cable didn't have to come off with it. Thanks to all the helpful folks on here, I realized that my white spacer was in the completely wrong place, and I had an unnecessary washer shimming things up as well. I pushed the spacer up to where I had the clip (position 3), made sure everything was snug, and set the washer aside. I put everything back together and let it idle for about 5-7 minutes in the garage just to get up to a temp where it didn't need the choke to maintain smooth idle.
After that, I started playing with the throttle position to see if there were any quickly detectable rough spots. The thing revved like it wanted to be a sport bike and sounded much, much better. There didn't seem to be nearly as much of a hesitation in the throttle, either. Assuming that this fixes the bogging, surging, and extremely poor mileage I've been getting, I'll call it a success. I'm definitely expecting to see some mileage improvements, since the spacer was essentially simulating a needle with the clip at the 75th position or so
Here's to hoping I'm done posting about carbs except to say "hey guys, I finally ordered that TM40"
-12,500 miles on carb and engine
- K&N air filter
- Stock exhaust
- Cut airbox
- Non-USA OEM needle from motolab with clip on third position