Adjusting the slackness of the chain is as important an aspect of chain care as lubricating is. Over a certain kms done, the chain tends to get loose. Of course, your owner's manual will have exact requirements for your bike, but the rule of thumb is about 1 to 1.5 inches of slack.
Why we need to adjust slackness of the chain?
You need slack because as your swingarm moves up to compress for a bump, the chain gets tighter. When a chain is too tight, it will bind on the sprockets, causing quicker wear of both chain and sprockets. A tight chain will also, over time, ruin your countershaft and your countershaft seal (the seal around the shaft that carries the front sprocket) and may even bend the countershaft. Also, a tight chain is more likely to develop tight spots. Tight spots are portions of the chain that stretch at different rates and cause binding between links.

So, why not just run the chain really loose?
Well, too loose and the chain runs the risk of flying off the sprockets. Bad news! Also, too loose causes a lot of slop in the driveline. Example: twist the throttle, short delay, then lurching as the chain snaps tight, then loose until you are under heavy acceleration. Chain adjustments are very important, even though it may not be something you need to do very often.


Explained in a tech jagron-free way, here is the method of tightening the chain on a Pulsar 220.

Put the bike on the center-stand. Move the wheel by hand through it's full travel and watch the chain.
Tools required-



First of all we have make this nut,as indicated in following picture, loose (just loose not remove) using the 22mm ring spanner (a normal spanner would also do) in a anti-clockwise manner






In the following picture (see the white arrow mark), there are two nuts together. Identify this nut which is bigger. It would be just next to the swingarm's end.



This is one of the nuts which actually tightens the chain. Use the 14mm spanner to tight the nut in clockwise manner-little bit and check the chain for the desired tightness. Readjust as per requirement.


Do the same on other side. This nut would already be bit free as it corrosponds to the similar nut on the other side. Again 14mm spanner.



The job is done. Chain would now be tight as you required it to be.
Now identify this smaller 12mm nut in the following picture. And tighten it against the bigger 14mm nut, using a 12mm spanner.



This is to be done on both sides. There is a glitch here which should be taken care of. When you tighten the 12mm nut against the 14mm nut, they tend to rotate together as a single unit. Following picutre depicts the way to check this-

Hold the 14mm nut with the help of 14mm spanner and the use the 12mm spanner on the smaller nut to tighten it against the bigger one (i.e. the 14mm nut)

Now refer to piture no. 3 where you made the nut loose. Its time now to tighten it to complete the job. See this picture-

(Do not forget to use the split pin if provided.)

Job done!
PS.1. DO NOT over-tighten the chain. You can tighten the chain with tools but it is not so if you want to increase the slackness (i.e. making it loose).
2. Do not run the chain dry. Lubricate it as required. O-Ring chains have, as you would guess, small O-Rings built into them. The O-Rings are used to keep grease and lube inside your chain (between all the moving parts). A chain that is ignored will eventually fail, typically by breaking. So keep lubricating it as and when required.

Caution:
1.Please do not forget to wear protective accessories while working with you bike, including gloves, shoes and a mandatory proper protection for eyes.
2.Do maintenance job in open with ample amount of light available. Sunlight is best for such purposes.

happy biking...