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Technical / 2001 yz125 riddle
« on: January 20, 2011, 11:14:55 AM »
To be clear, this isn't a thread of me asking for advice, since I have figured out the issue (and I will tell. .. after a few guesses for fun). .. just curious if anyone would actually guess the problem with my 01 yz125.
When I went to test ride the bike, I had some trouble getting the bike to start. The owner indicated that I shouldn't crack the throttle AT ALL during the kick stroke (I have a habit of blipping the throttle just a little bit near the bottom of the kick.)
With his advice, it started and blipping the throttle would keep it running. I took it for the test ride and it SCREAMED down the street, but bogged and died when I let it get back near idle. I figured that the jetting was off and I'd get it straightened out once I got the bike home.
At home, I'm adjusting the air fuel screw and the pilot jet. .. I end up chainging the pilot jet from a 25 to a 27.5 to a 30 to a 35, and there's really no noticeable difference. .. on any of these jets it would run the closest to correct with the air fuel screw turned almost all the way in.
I went through the electric system and checked everything out. . all measured within spec.
Thinking that the pilot circuit could be plugged, I did a complete disassembly on the carb and cleaned that circuit out fully. No change. The bike still requires the same starting procedure and acts very lean from idle to mid-throttle, but runs great above that.
When I went to test ride the bike, I had some trouble getting the bike to start. The owner indicated that I shouldn't crack the throttle AT ALL during the kick stroke (I have a habit of blipping the throttle just a little bit near the bottom of the kick.)
With his advice, it started and blipping the throttle would keep it running. I took it for the test ride and it SCREAMED down the street, but bogged and died when I let it get back near idle. I figured that the jetting was off and I'd get it straightened out once I got the bike home.
At home, I'm adjusting the air fuel screw and the pilot jet. .. I end up chainging the pilot jet from a 25 to a 27.5 to a 30 to a 35, and there's really no noticeable difference. .. on any of these jets it would run the closest to correct with the air fuel screw turned almost all the way in.
I went through the electric system and checked everything out. . all measured within spec.
Thinking that the pilot circuit could be plugged, I did a complete disassembly on the carb and cleaned that circuit out fully. No change. The bike still requires the same starting procedure and acts very lean from idle to mid-throttle, but runs great above that.