Check the chain and sprockets for wear. When you have an endlink/masterlink its easier to get the chain of the bike. Cook it in oil or degrease it with (stuff/thinner) and properly clean it and dry it with heat or in the sun. Dirt on the outside is not the problem, it's the dirt that stays between the links where de sprockets touch the chain and the links themselves (the movable part)

I don't drive in rain of winter conditions. So my chain doesn't get real dirty.
I lubricate it a couple of times a year. Lubrication is more important than cleaning.

Teflon based grease always works for me, when I spray it on and leave it there for on our then it looks like the chain sucks it up. Afterwords I clean the chain and sprockets again because grease on the outside only attracts dirt.

When I go on a roadtrip for 2 days or more I always bring my chaingrease with me.
I also did 640 km (GSXR) on one day without rain and the chain did not need lubrication afterwords.

It's easy to judge not rocket sience.

 

If you do go to replace it get a o-ring chain,it keeps the dirt out.If you have a master link with the clip you can take it apart to see the wear.If your almost to the end of your ajustment on the rear tire is another way to tell if its getting time for changing.The chain should have about a inch of play in it when set then set on the bike to make sure it don,t get tight.Gears should look the same front to back of teeth, if hooked they are worn the front wears worse.

If in dought change the chain & sprockets chain breaking can do damage & or lock up rear tire.I used a chain wax about once a week on my last bike but that was overkill & I was always cleaning it off the wheel,chain & sprockets.I would only clean chain in kerosene if I was taking the tire off or something,which was to often on that old bike (79 XS)

 

Ok, I should mention..

This bike has been modified like crazy...I can't tell you what was done to it, but I'll make my hubby post in 2 days when he has his days off.

Apparently it will go a heck of a lot faster than it was meant to, but I don't drive all that fast so that didn't matter to me,therefor I didn't pay attention to that part of the conversation LOL! but it has a new bigger chain, so I guess the sprockets were swapped out too.
I will get him to write it all down, or post it on here for me so you will know exactly what has been done to this girl.

 

On my ninja 650:
chain lubed every ~400 miles

Chain adjusted as needed. Checked tension at each chain lube.

 

I have owned a lot of large displacement chain driven bikes. Chain maintenance frequency depends on road and weather conditions and how many miles are going on the bike per month.

Chain wear is something you need to either have pictures of what it looks like, or know what a new chain looks like so you have a reference point. It would not be a bad idea to ask the technician servicing your bike to inspect the front and rear drive gears and the chain for wear and advise you.

Cleaning it is probably the most critical part of chain maintenance. Lubricating it is the easiest part. To clean an O-Ring chain, use kerosene or WD-40, and make sure it is completely dry before lubricating the chain. Do not use compressed air to dry it.

There are many good motorcycle specific chain lubes on the market. PJ1, Maxima Chain Wax, and Bel Ray Chain Lube are three that I have used that I think are very good. In a comparison and test of chain lubes, PJ1 (black label) was rated the highest by Motorcycle Consumer News. But I know a fella who swears by WD-40 (it has no resistance to fling off, but this guy liked it because it cleans the chain).

I have an OEM chain with over 20,000 miles on it and it is still in excellent condition, so with proper care the chain can last a long time. I expect this chain to at least reach 30,000 miles before it has to be replaced.