Is it a pain like the raptor??

 

Yeah its a pain... I've never adjusted a raptors chain but I have on a warrior and the YFZ seemed the same. Loosen two bolts on the swingarm side and then adjust how far back you want the axle with the adjuster screws.

The biggest issue with the YFZ is that one of the bolts you have to loosen in the swingarm is tucked under a ridge that doesn't allow you to get alot of leverage. And in my particular case I think Hercules tightened the bolt down in the factory because I actually broke a break over bar trying to loosen it.