I purchased the kz yesterday. The guy i bought it from said he had her running last year a couple times no problem but just didnt have the time to get her on the road due to lack of title. today when i went to start her up, third kick and she came to life. as i was about to pull out of the garage my buddy made me stop. Oil was pouring out at what appeared to be the junction of the shaft drive and the trans. I ran it for about 5 mins before i had to shut her down so she wasnt leaking instantly. but can that seal go without notice? the leak was at the bottom of the junction which is in the center of the photo. as a reference point, the bottom of the picture is right above the front left footpeg

 

If its been sitting for a while the seals can dry rot. Once you get stuff moving again they may not survive. You should be able to swap the seal and ride.
Welcome to KF!