TrailRider2

Yeah, Thanks. Ill make sure I clean it first and than go from there. Some Yamaha owners say that these small carbs are way to lean from the factory. I've heard that people who get larger main and pilot jets eliminate the need for the choke.

Thanks for the responce! Yeah...Now I need to find out what size pilot and main jet to buy. Do you know where I can go to find this info.?

My TTR50(13mm Mikuni VM carb.) will not start without the choke on. After less than 10 min.I can shut off the choke and it will keep running. The idle speed screw has to be set a little on the high side to keep the bike running. The air mixture screw has absolutely NO effect on my set idle speed. Otherwise the bike does run ok. I live at 3900 ft above sea level in the Mojave Desert. Do you think the bike is running very lean? What size main jet and pilot jet should I use. Please Help.