Motorcycle Repair: not running right, v45 magna, crank case

Question
1985 v45 magna  runs good cold, blows out black smoke when warmed up. there is a faint smeell of gas in the oil. also barely runs when  hot.

Answer
Hi Fred

Smell of gas in the oil usually means the carbs are over-flowing and leaking into the crank case.
Black smoke can either be burning oil (does it smell like burning oil), or it can mean it is running very rich from too much gas.
If its been a while since the carbs have been cleaned, then they should be removed from the bike and cleaned thoroughly.