Vintage Dirt Bike Q & A

I picked up a new smoker. Its a 250 and has been sitting for 15 years. The former owner said it was running when he stopped riding it. I pulled out the air cleaner and it looked like it had just been oiled and even had clean grease on the bottom. I checked the oil and it was full and clear. The tank had some rust particles. I tried to clean it out (there was some accumulation in and on the petcock).

I put some gas in and it started after 5 kicks. It only runs with the choke on and will die after a minute or so. It isn't a pulling a steady stream of fuel in as seen through the hose and fuel filter.

I pulled the carb and am about to go through and clean it. What should I be looking for that might cause it to only run when the choke is on?

The pilot jet and/or pilot system passages may be plugged, and the float level may be low as well.

Ray

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'74 CR125M (175cc), '75 MR175, '82 RM250Z, '08 YZ250F, '14 Zero FX electric, '14 Zero MX electric, '18 Alta MXR electric

I think it was related to the air screw and Pilot. I took it apart and found goo on the air screw, so I cleaned it out again and it ran ok. It wasn't sucking fuel into the carb very well, so I took it apart again. I completely dismantled it including the choke. Blew it, pipe filtered and adjusted the float. Now it works great.

I think it was related to the air screw and Pilot. I took it apart and found goo on the air screw, so I cleaned it out again and it ran ok. It wasn't sucking fuel into the carb very well, so I took it apart again. I completely dismantled it including the choke. Blew it, pipe filtered and adjusted the float. Now it works great.