Does it stutter on the top end or does is feel fat? Sounds like you need to do some jetting to me. I don't think I have ever seen a 70's 2 stroke from Japan that wasn't overjetted from the factory. If you haven't tried it yet, pick up 1 richer and 1 leaner main jet. Start with the richer (bigger) jet and see if it makes it worse or better, my bet is it will be much worse. If I am correct, go to the 1 step leaner and keep going until it runs out clean.
Once you have the main jet dialed in, then go to work on the pilot and/or needle. I would work the same system on the pilot and see how it affects the bike, then work from there.
Yes, you will have a handful of jets when you are done, but it will feel good when it runs correctly. You will also learn how to pull the carb quicly and how little you need to disconnect to do it. I became quite good at the parking lot pull...leave the fuel line and throttle hooked up, loosen the carb, put a rag under it, pull it out far enough to remove the bowl and replace the jet. All told I could do a Yamaha DT in less than 5 minutes, a XR650L in roughly 8 (by leaving off those ugly scoops).
If the bike is not consistant in its running...sometimes good, sometimes bad, you will need to look at the spark advance system to see if it is operating correctly. I believe this was a common issue to the big ts/tm series (though this is from memory...they could have fixed it by 76).