Hey... Just picked up a 1991 yz125 a few days ago for a deal at $300... The bike has been sitting for like 5 years. It is in good shape. I pulled the carb, looks pretty clean. Put a new plug in it and cleaned the fuel lines. Stuck the carb in carb cleaner for the recommended 20 mins. I also checked the reed valves and they are opening. Put it back on and bike starts but still will not run at idle. Going to check the jets tommorow and do some more adjusting to the idle and Air screws.Also going to check for leaks.Bike runs strong off idle when choke is on. I have been reading alot about what to do on here in this situation and have studied the carb assembly diagram. I do not have a book or owners manual so I am flying by the seat of my pants, although; I am pretty a mechanical guy. Any suggestions? :blah:
1991 YZ125 Runs strong will not idle without choke
- Thread starter FrankD247
- Start date
Ol'89r
LIFETIME SPONSOR
- Jan 27, 2000
- 6,958
- 45
Clogged pilot jet.
Pilot jet is the little jet that sits right next to the main jet. Sits down in a hole and requires a small flat-blade screwdriver to remove. Remove the pilot jet and make sure you can see daylight through the center hole. Also, remove the air adjustment screw and make sure the passageway is not obstructed. The air adjustment screw hole and pilot jet holes are connected. Use air pressure to insure the orifices are not blocked.
Pilot jet is the little jet that sits right next to the main jet. Sits down in a hole and requires a small flat-blade screwdriver to remove. Remove the pilot jet and make sure you can see daylight through the center hole. Also, remove the air adjustment screw and make sure the passageway is not obstructed. The air adjustment screw hole and pilot jet holes are connected. Use air pressure to insure the orifices are not blocked.
