Hey guys,
when I got this bike it would idle really high and shut off when choke disengaged. Cleaned carb & 2nd kick had it running. Was idling low so I turned throttle screw clockwise and you'll see what happens next in the videos below.
Bike: 1998 yz125, big bore kit 144cc?
Known problems to date (not sure of relevance to issue):
1) 2 nuts and bolts missing in the intake boot, (not sure if air leak could cause high idle)
2) Hose clamp for intake boot missing
3) Main jet is a 330, Revzilla calls for 340-350 (part coming today)
4) Pilot jet looks possibly bent.. have a new 47.5 coming today. (Revzilla calls for 45-50)
5) Tension spring + both o-rings missing from exhaust pipe
6) Throttle spring in carb is bent (can feel when opening up throttle on grip)
7) Air vent hoses on carb missing + fuel vent hose.. but just cleaned carb.
Videos of issue:
https://streamable.com/2f0ve
https://streamable.com/7fa5a
Note that at 00:09 of the second video, I hit the kill-switch and let go to take one more crack at the throttle screw. That's the reason for bogging down.
Other relevant concern:
I wasn't sure how much to tighten the throttle cable at the top of the carb.. I noticed that tightening it dropped the slide and loosening it, raised it. Where is the slide supposed to be at rest position?
(i.e: Halfway, all the way down, etc).
Any and all help is greatly appreciated!
I'm just starting to dive into the world of internal combustion engines!
those clamps need to be right. as others said air needs to be in the right spots
