1) as far as the oil goes... i have a 78 750 and the oil pump has to work for the oil to pull down out of the reservoir into the block and all so make sure you put a couple of quarts in the reservoir and then crank the bike for a few seconds to minute or so. this will pull through the oil. then check your level and add as needed repeating the short crank and rechecking. continue this until the level is right.
2) if there is gas leaking out of the float bowl and it only happens sometimes there are a few things to check. the drain screw on the bottom of the carb (if it's like my 750) has to have the proper shape out toward the tip or it will/can leak. check to make sure that the end of the screw is tapered properly and is free from pitting/scarring.
if there's gas coming out around the screw itself, you may need to replace the little o-ring on the screw.
check your float bowl height and the condition of the float needle. if the float bowl is not raising up enough with the level of the gas, it may fail to cut off the flow. if the float needle has a ring worn in the tip and is not a smooth taper, it will also leak some. --- also check to make sure your floats are not sticking. if you feel any resistance in the float bowl when you push it up and down, spray a little WD 40 on it and work it up and down for a while gently. it should work out most of the corrosion.
check the pipe coming out of the bottom of the carb for cracks as well.
------ when my bike was doing the same kind of thing, it had two of these problems. the drain screws were pitted AND the float bowl needles had faint little rings in them. both of these contributed to the leaky carbs.
good luck!
