Problem with starting my honda bike?

Hi. I have a honda cg125. About a month back it started giving problems to start (cold start that is in morning) Before i would just press the start button and it would start flawlessly. Now when i press the start button it starts then cuts out. Start again idles for a while then cuts out. I then have to end up using the choke. The problem is not the battery. Replaced spark plug, brand new ngk iridium. I have absolutely no idea what this problem is. I took it to the honda official service shop, they serviced the carb but i still have the problem. Please help!

Also i hear a whistling sound when i start it i.e is cold start i'm talking about. During the day it rides perfect.

Help.

Added (1). Yes i know but before i didn't have to use the choke at all. The engine could have been really cold and one touch of the button it would start. I want it to go back the way it was.

The choke is for starting when the engine is cold. There's no problem.

>"I then have to end up using the choke."

What did you think it was for, hanging your helmet on?

Even Honda mechanics can't fix operator error.

The choke is a device to make the fuel: air mixture rich (by increasing the proportion of fuel) to allow the bike to start, once it is warmed up return the choke and ride it.

Do yourself a favour read your owner manual it contains many interesting snippets.

Always use the choke.
The choke is necessary to start a cold engine - even if the bike was in the middle of the desert.

When starting from cold it is normal to have to use the choke - that is what the choke is for

Your leaning out (more air then fuel in the balance) somewhere if you need the choke to run.
You maybe getting a vacuum leak developing, inspect the carb boots to heads good.
A clooged fuel filter or restricted jet will also throw you lean.

Using the choke cuts the air intake, and if it runs better that way, it's telling you it wants less air, more fuel somewhere.

Cold start USE THE CHOKE WTF?