1981 yamaha xj650 maxim

my 1981 yamaha xj650 maxim is leaking oil into the air box and currently doesn't want to start all the time. When I do manage to get it started it won't idle and I have to pump the throttle or it dies. I have owned this bike for a few months now an it developed these issues just a couple weeks ago. I used to ride it around town quite often. I took it for a linger distance ride witch was about 40 miles round trip and that is when it started the oil leak brought it home it kept leaking more oil. Few days after that it stopped starting and refuses to idle when it does start up. Any help is greatly appreciated thank you.

 

The breather tube is most likely how the oil is getting into the airbox. This could be overfill of the oil , blow by from worn valve seals Or rings. If you only ride short distances carbs can get gummed up from lack of use , ethonol fuel can turn to gum sometimes in a short period of time. I recommend lifting the tank , remove fuel line from the petcock. Get a large meat syringe fill with MEK or Acetone squirt down the fuel line into the carbs do this several times let this set for around an hour . Open the float bowl drain screws., Drain and reconnect fuel line , put petcock to PRI . Apply choke and see if bike starts , you should also check the spark plug to see if any are covered in oil , if so clean or replace.

 

Is it just a little oil, or a lot?
Does it smell of gasoline?
When on the centerstand does the sightglass show a proper oil level, or is it overfull?

 

I would do a compression test too just to make sure they are within spec to check rings etc. Did you service the bike when you bought it?