tukarthik
If your Classic 350 is a newly made one (after 2009) it has the new UCE engine.
These engines have an automatic decompression device built into the exhaust camshaft.
This is activated by a light spring pressure when the engine is not running and deactivated by centrifugal force as the camshaft is rotating after the engine starts.
Normally, the device is made to retract after the engine reaches a idle speed over about 750 rpm but with cold oil, they will sometimes get stuck in place by the thick oil and stay in the "active" mode and make a TIC, TIC, TIC, sound.
Usually, slightly 'revving' the engine will cause the device to retract and the noise will go away. If it doesn't, as you've found, after the oil heats up the centrifugal force will retract it to its "running" position.
By the way, if your motorcycle is a UCE model you should post your questions in the area of the forum titled "Bullet with the UCE engine".
It's confusing but this area of the forum is intended for the old Iron Barrel powered motorcycles.