Yes, that's about right. It is always a good idea to hold the bike upright sitting under it's own weight and have a feel of the slack with you finger after adjusting it on the side stand. It will get tighter, and will just about touch the swingarm at the midpoint of the lower run with a little force.

If you've got a mate handy, it's even better to check it with someone sitting on the bike. It should not touch the swingarm at all. The slack should be about 25-30mm with someone sitting on the bike. If you're running the bike loaded, then check it with all you gear on board too.

It all approximate though, you tend to get a "feel" for it after a while.

Main thing is to make sure it's not so slack as the chain is at risk of running off the sprockets when the suspension is fully extended (slack at its greatest) and not so tight that it puts a strain on output shaft and sprocket carrier bearings when compressed and the swingarm is parallel to the ground (slack at its minimum).

BTW - to XT660.com!

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