Sudden White Smoke on Start

[Italianzero]

Hello everyone! I haven't posted in a while as I got busy with work but now trying to get back to the project. My '81 XS400 was running great after a a carb rebuild, but then it sat for about 7 months. When I started it up again a bunch of white smoke was kicking out of the exhaust. I let it run for a bit and warm up and it just kept coming. No visible signs of any leaks or other issues. Engine sounded normal and idle was mostly steady.

Any advice on what to look for first? Head gasket? Valve seals? What is my best shot at diagnosing the problem?

Thank you in advance!

 

[CaptChrome]

White smoke usually means not enough fuel. So look at clogged screens at the petcock, clogged screen under the float bowl fill valve seat assembly and a possible clogging of the pilot jet.