I'm going riding with my wifes cousin this weekend for the first time and he called and wonderd if I could help him with a problem he is having with his YZ 125, 1998 or 99 he says it idles fast. He has adjusted the air screw several times and it does not stop the idle. When he rides it he says it runs good not fouling plugs or running lean. Could the carb be leaking some air in and if so where? We are riding Saturday so a quik response is needed. Thanks :flame:
yz 125 idle problems
- Thread starter crb
- Start date
MX-727
LIFETIME SPONSOR
- Aug 4, 2000
- 1,811
- 13
Adjust the idle screw (throttle set screw) instead of the air screw. It's the screw outside the slide portion of the carb that has a locknut on it.
Go to the following link and it's number 14 on the schematic.
http://216.37.204.205/Yamaha_OEM/YamahaDB.asp?Type=13&A=162&B=7
Go to the following link and it's number 14 on the schematic.
http://216.37.204.205/Yamaha_OEM/YamahaDB.asp?Type=13&A=162&B=7
Nevada Sixx
Member
- Jan 14, 2000
- 1,033
- 0
there is an air screw, and and idle air screw,, hope he turn the right one...other than that, sometimes a new pipe can make a bike idle high, or maybe the jetting is to lean on bottom...
Nevada Sixx
Member
- Jan 14, 2000
- 1,033
- 0
also, you may want to check the reeds and for air leak around the carb.
SiCnTwIsTdYz
Member
- Apr 10, 2002
- 322
- 0
well mine idles with the choke on, without the choke it will stall out if i just let it idle so i have to keep revving it, its not really a problem
The B.S. Grows deeper every day.
:|
1. Make sure that you have no air leaks. 2. Make sure that you have the proper size pilot jet (CLEAN), that your carb is CLEAN, that includes all of the air passages and such. 3. Adjust your air screw according to your manual. (usually to were it idles the smoothest and responds the best) 4. Adjust the idle screw to your liking. You should be rollin then. ;) But remember, don't let the bike sit and idle for too long (more than a minute or two once warmed up) or else it will overheat for lack of air passing through the radiators.
Despite what people will say, MX bikes CAN and WILL idle, some people however just prefer that they don't, I leave that up to them.
:|
1. Make sure that you have no air leaks. 2. Make sure that you have the proper size pilot jet (CLEAN), that your carb is CLEAN, that includes all of the air passages and such. 3. Adjust your air screw according to your manual. (usually to were it idles the smoothest and responds the best) 4. Adjust the idle screw to your liking. You should be rollin then. ;) But remember, don't let the bike sit and idle for too long (more than a minute or two once warmed up) or else it will overheat for lack of air passing through the radiators.
Despite what people will say, MX bikes CAN and WILL idle, some people however just prefer that they don't, I leave that up to them.
If after all the above your bike is still idling too fast, you might check the throttle cable for kinks or just being too tight. Take the fuel tank off and move the cable around to make sure there is plenty of slack. Also, YZ's had a problem with the Throttle cylinder sticking, make sure your is not.
