Yz125 has no bottom end and won’t idle

Create New Tag

9/27/2018 5:05 PM

I picked up a 2003 yz125, have gone through and cleaned everything up including the carb and the bike just won’t idle even after adjusting the air screw. I just got my new jets off pro circuit recommendion of -430 main and 37.5 pilot and will be adjusting my needle when I install these. But is there anything else it could be other than jets? Because it runs perfect on the pipe but anything low isn’t there.


9/27/2018 5:48 PM

This probably isn’t much help, but I’ve never had a 125 that would idle.


9/27/2018 9:45 PM

Likely jetting/air leak related. Could your power valve be stuck open?
I presume you're also adjusting the idle screw? On the TMX carb it physically holds the slide open at a higher level.

Your 125 should idle just fine once everything is correct.


9/30/2018 8:16 AM

No bottom end power could be from a broken PV linkage.