i'm not sure if it's the same on a 660 or not but this is how to adjust the chain slack on a raptor 700. it's a pretty easy job but i have seen a couple of question on how to do this, so here is how i do it.
tools needed for this job.
![](http://i.imgur.com/oBPHosp.jpg)
take the 6MM allen wrench and start by loosening the carrier bearing pinch bolts. i like using the ratchet drive allen key with the extension because it gets my hands away from the swingarm so i don't hit my knuckles on anything.
![thumbs up :thumbs:](https://raptorsource.com/forum/Smileys/custom/thumbsup.gif)
![](http://i.imgur.com/UiM4cYl.jpg)
after loosening the bolts find the open hole in the side of the carrier that looks like this.
![](http://i.imgur.com/kAeMMjy.jpg)
put the 5/16" rod in that hole. if you don't have a 5/16" rod then you can use a roll pin punch like pictured with the tools.
![](http://i.imgur.com/9SU0IKX.jpg)
next you will need to push the raptor either forward to loosen the chain or roll it back to tighten the chain.
then take the tape measure and put it about in the center of the swingarm like so:
![](http://i.imgur.com/g98mSr6.jpg)
while holding the tape measure there push the chain down and then take the measurement and then pull it back up and take that measurement. the measurement should be .98-1.38 in. i like to set mine at about 1in. to 1 1/4in. after you have your measurement set take the 5/16in. rod out, and you are ready to tighten things back up.
tighten and torque to the bolts in this order. using a torque wrench (sorry not pictured with tools) you should torque the bolts to 15 ft/lbs.
![](http://i.imgur.com/w30lb5d.jpg)
i used all the specs that the yamaha service manual uses in this how to.
if you have any questions about adjusting your chain with this method feel free to ask.