Engine Heating and smoke coming from the exhaust

[djudge]

Hi,
I have recently bought a Yamaha XS400 1982, It's my first bike ever and I just have a very little knowledge of mechanical work. My bike heats up very fast if I go for 5 to 10 km's, a smoke starts to come out of the exhaust area. There's enough engine oil so I don't think that is the issue. I am not sure what else to look for.
Could you guys please be able to help me out? I would much appreciate it.

Thanks

 

[BBS360]

The bikes do get hot.

You'll want to download the Haynes and oem service manuals. Check everything that can be checked and do the motor diagnostics.
Pull the spark plugs and compare to the diagnostic photos in the Haynes manual.
Check the compression on the cylinders, wet and dry.
Check the valve clearances.

That'll be a start. Let us know the results.