After parked over night, when I start the bike for the first in the morning or at noon, as engine starts to fire up, I hear clunk noise and a jolt felt though my hand on the clutch.

Any one know if what this is about?

Yeah it's the amazing quality of the Suzuki bikes.

It suddenly began to do this two days ago. Never happened before.

Goats, open the damn left side and fix the goddawful starter clutch before that clunking vibrates the alternator and stator loose and turns the inside of the engine into an enchilada.
Right now you will get away with a starter clutch, if that happens and you get full blown goats it will be starter clutch+alternator+ stator + a whole bunch of grief cleaning all the magnet and wire bits out of your engine.
This is exactly how mine died 5 years ago. Jolts form the clunking shook a perfectly good rotor magnet into comming loose, hitting the alternator and destroying both. Get the sliding hammer tracked down and get yourself on the shipping list.
Cool.
Buddha.

Thanks for the tip Buddha. This doesn't happen when I start the bike when the motor is warm. Was your bike like this too?

What exactly am I supposed to do with the starter clutch? Should I tighten the starter clutch?
What do I need a sliding hammer for?

How long did the symptom last on your bike before your motor went goat poop?

Well I don't know if understand this correctly, but try charging your battery first.
When my battery was in a bad shape I had that clanking noise too, some times.. starter clutch they told me.
After I charged it, it was fine 

Mine was doing it for near about a year. I also had teeth marks on the gear center ... aka wear from just miles and miles ... well starts and starts.
I dunno how charging the battery can do it. But clunking @ start up has to be fixed before the vibrations shatter the rotor. That is pretty much it. So if it quits with charging the battery, leave it be.
Cool.
Buddha.

Thanks a lot guys.
Recharging my battery. The battery fluid level is little above the low line on my bikemaster battery. Wonder if this was the culprit.

Bhudda, so if I get to fix the starter clutch, what exactly am I supposed to do to the clutch with the sliding hammer?

Search sliding hammer on this site.
But its needed to pull the magnet off the crank.
Cool.
Buddha.

So take the starter clutch out with a sliding hammer and...? Do I adjust or replace it?

3 springs (yes looks like ball point pen springs, but so do the damn fork springs on this bike), 3 rollers and 3 pins, and that pack costs 27 whoppers ... yea ... replace with new.
Cool.
Buddha.

Wow, glad I read this thread. I've been having the same issue. I thought it was just normal because the bike is cold since it doesn't happen once she's warmed up.

I would get a loud clunk on the first start but on the second she would fire up fine and no sound at all restartarting once warmed.