yz125rider77 said:
on the website what does "pos" mean and is there different size fuel mixture screws?
Depending on the context, "pos" could mean "positive" or it could mean "piece of .....".
As for fuel mixture, the idle circuit is usually adjusted with a screw. The metering needle, which adjusts the mixture a bit between low and mid range, is adjusted by moving the needle position up and down by changing the "clip" position. The main jet is usually buried in the carb and is adjusted by removing it and replacing with a different one.
Rod