Engine produces a generous amount of white smoke

[Love karts87]

Hi I am new to “diy go karts”and I recently bought a brand new lifan 212cc engine for my mega moto 80 mini bike from go power sports .i put a stage 1 air filter and a straight pipe on it .it ran fine for about two weeks until i heard a scraping from the engine.i took the head off the engine and everything was perfectly fine.
I put the engine head back on and started it.it fired first pull but then white smoke poured out the exhaust.so any ideas on how to fix?

 

[Whitetrashrocker]

Your burning oil.
Possible culprits:
Blown head gasket.
Leaking valve seals.
Worn piston rings.

Are you blowing oil out the breather?

 

[Love karts87]

It’s a brand new engine but the valves might be leaking I’ll check soon

 

[Love karts87]

Thanks for the help!

 

[Darren]

sounds like broken rings

 

[Sparkwizard]

When you removed the head, did you put a NEW head gasket on it, before you put the head back on?