!st was check the valves. Lots of incorrect information out there about the TTR 250 head. Its a YZ bucket and shim over valve under the cam, nice and simple, same shims as all the YZ and I would guess many road bikes. 5,000 unknown miles on my bike each valve was exactly at min. clearance, so its was just right to go next size small on each shim.
Next was the carb, and posting here to thank every body that chimed in on carb issues. The needle and seat were replaced, the gas screw/idle circuit adjustment had been abused and I had to replace it. I used round large Mikuni jets because I had them, didn't fell like the same thread, they seated ok but with a little toooo much resistance for my taste. Used the odd long Mikuni pilots and went from the stock to a 55. So far seems good. Looks to be a poor excuse for a carb, but if it runs ok and gets good gas mileage,..........well ok.
