Planet Minis

ysr90 · 06-13-2009, 04:43 PM

I have a yamaha ysr 50 that I just got back from my buddy since he never paid me for it. It ran like crap and wouldn't idle. So I replaced the rings, had Donelson Cycles check and hone the cylinder, cleaned the carb, and replaced both crank seals. Now it idles with the choke on but as soon as I push the choke back in it revs up high and then dies. I have tried 2 different carbs and both do the same thing any suggestions? I tried spraying carb cleaner around the case to look for a leak but found nothing. The car has the stock 120 main jet, needle clip is in the 4th position, and the air fuel screw is backed out 1 1/4 turns.

johnson05 · 06-13-2009, 08:29 PM

Try turning in the air screw all the way. Does it make it idle lower? You may have an air leak or you may just need a richer pilot jet.

dixon · 10-18-2009, 04:13 PM

My brother bought this bike and it turned out that the idle screw and mixture screw were reversed. Swapped them around and now runs like a champ.

06-13-2009, 04:43 PM	#1 (permalink)
ysr90 PM Newbie Join Date: Feb 2009 Location: St. Louis MO Posts: 1	Yamaha ysr50 2 stroke help I have a yamaha ysr 50 that I just got back from my buddy since he never paid me for it. It ran like crap and wouldn't idle. So I replaced the rings, had Donelson Cycles check and hone the cylinder, cleaned the carb, and replaced both crank seals. Now it idles with the choke on but as soon as I push the choke back in it revs up high and then dies. I have tried 2 different carbs and both do the same thing any suggestions? I tried spraying carb cleaner around the case to look for a leak but found nothing. The car has the stock 120 main jet, needle clip is in the 4th position, and the air fuel screw is backed out 1 1/4 turns.

06-13-2009, 08:29 PM	#2 (permalink)
johnson05 PM Newbie Join Date: May 2009 Posts: 72	Re: Yamaha ysr50 2 stroke help Try turning in the air screw all the way. Does it make it idle lower? You may have an air leak or you may just need a richer pilot jet.

10-18-2009, 04:13 PM	#3 (permalink)
dixon PM Newbie Join Date: Apr 2009 Posts: 37	Re: Yamaha ysr50 2 stroke help My brother bought this bike and it turned out that the idle screw and mixture screw were reversed. Swapped them around and now runs like a champ.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)