My 94 VMax600 is running really rich on oil. Leaves a large black slick on the floor after idling for only a short time. When I pull the cable, with the adjuster bottomed out, I can't get anywhere close to the spec of 27-29mm. I don't see any issues with the cable. It was set at 20mm when I got the sled. 
it could be your oil pump has failed. most yamahas oil pump, when they fail, they fail in wide open to save the motor.