Folks, what all is needed for chain and sprocket replacement? Do I need any special tool for this job? Any DIY thread etc?

Nothing rocket science about it just remove the nut on the front sprocket before you remove the chain,this way you can use the rear brake to keep it from rotating.There is a lock tab you will have to bend back to remove the nut.

As far as tools just a big enought socket and a long breaker bar or a impact driver.

Also make sure you give it plenty of lube.

is there a split link in the chain?

I don't know at the moment if there is a split link, can't see in my current one it is too dirty. Is it like I have to break my current chain to finally remove it? I have all common sort of extn bar and sockets.

If it's the orignal chain there is no split link,just take a grinder to it and cut it, the new chain will have a split link in the box.

How do I unlink the new chain to fit it in and also do I need to take off the wheel for changing chain if it is link attached