I am thinking about buying a new 125cc dirt bike. Probably a YZ or RM. I only weigh about 135lbs and would like to know if the suspension and the settings would be okay for a beginner rider.
Would I need to mess with anything or should it be fine for a beginner?
I think you're safe to get the bike and just ride it. Try setting the rear sag alittle on the tight side, (95mm) and start with all the clickers at the stock settings. By running the shock sag a little tight, you won't throw the rear to far out of balance with the forks.
For your weight you need softer springs front and rear. Most bikes also benefit from a revalve. If done right, revalved suspension is plush over braking bumps but still maintains good bottoming resistance over jumps. If i was you i would go for the yz. I think they last longer and will have better resale value in the long run.
Micah, after you buy a bike and before you do anything else take the time to learn how to properly adjust your stock suspension. Then evaluate how it works whats good whats bad then you can make an informed decision about what to change .The workshop manuals are very informative . These days bikes come pretty well suited stock (although you are a bit lighter than most riders) and can often be put in the hunt just by proper setup. SAG CLICKERS OIL HEIGHT ETC. good luck.