Suzuki Club UK

Hello
I have an old sj413 that i did not use for almost 3 years. when i turned on the engine recently a very bd smoke that hurts the eyes was came out. i could not even drive it for 5 km.
anyone has any idea

I guess a load of oil has wept into the cylinders from the head through the valve stem oil seals or a breather or the PCV valve has blocked.