72 GT750J Leaking oil through the exhaust connecting tubes

[artsmokes]

Hi I just joined and hoped I could pick your collective brains.
I've owned this 1972 GT750J since 1972 I rode it a lot when I was younger. It sat in a shed for about 15 years while I worked and raised a family
I got it running about 5 years ago and put it back in the shed. During that time mice got into the air box and ate through the filter and used the carbs as a latrine.
The carbs are stuck and junk. I found some on ebay and they are real nice.
Now the problem:
I got it to run, barely. There is so much oil coming through (hence the ratty running) that it is dripping through the exhaust connecting tubes in the front.
I'm going to pull the muffler baffles to make sure mice did not set up housekeeping but I don't think that is the problem.
Any ideas, or help would be greatly appreciated

[GTandcbr]

Hi. Unfortunately its very likely that with the bike sitting for that long the crankshaft seals will be shot. Once they are damaged oil from the transmission will be drawn into the cylinders. Dont be fooled by the fact the engine runs as they quite often do. Its very likely that when you started it 5 years ago the seals were damaged then. There are things you can do before starting the motor to protect the seals like filling the crankcase with diesel to soften them first. Obviously it sounds like that may be too late for you now. I'm afraid its an engine teardown and replacement seals job. You can check first that it is the seals but having a leakdown test before taking the engine apart.
Good luck