When the bike starts first thing getting a bit of smoke in the left exhaust for a few moments then OK the plug looks a bit sticky
Usually a worn inlet valve guide.
The engine as just been rebuilt
Check again after a few hundred miles. It'll probably be OK.
A reconditioned engine will take time for the new parts to bed in properly.
New rings can take several hundred miles.
Hi Fereday,
What oil are you using?
Regards.....