When I first saw the bike it didn't run very well at all. The owner let me take the bike see if I could get it running right because if it didn't I wasn't buying it. The tank was full of rust and gunk. Cleaned that out and took the carb off and cleaned that also. It ran great with just a little miss. I bought it and have enjoyed it for the last 2 months. I just decided to replace the jets and o rings because I did a quick clean up to see if it would run before. When I put back together it started fine idle fine but would only start revving past half throttle or more. Otherwise from idle until that point it would be flat. Found a washer laying by where the slide and needle jet were. There was only a spacer, c clip and thin washer on the needle jet. Drawing shows 2 washers. This 2nd one was thicker it must have been between the spacer and slide and fell out when I took it apart. I reinstalled it that way and the bike runs better, but still has some hesitation right off idle. Is it normal to have that 2nd washer in that position. It's a stock Mikuni carb. Also doesn't look like it has another clip position. Can you also adjust the pilot screw from stock amount of turns to help performance.