I've got a 73' RD350 that I got running not that long ago. I've rebuilt the carbs and it runs, pulls...etc. I'm having an issue where it doesn't return to idle very well. I have to put it in first and slowly let out the clutch to calm it down. When warm, it'll stay where it's supposed to idle (1.5k) if not it shoots up kinda high (4-5K).
Sticky floats maybe ?