http://www.denniskirk.com/jsp/product_c ... mmyId=6736
http://www.psep.biz/store/john_deere_sn ... cables.htm
Any local power sport dealer would also be able to order one.
There are three lines that come off the oil injection pump. Two connect between the carb and pistons. The third connects to the lower part of the case behind the water pump. The one that connects to the lower part of the crankcase supplies oil to the inner crank bearings and I think it ends up lubing the wrist pin bearings also.
Me personally I check the oil injection system over to make sure it functions and run like 100:1 premix (with oil injection) for piece of mind. Everyone will have a different opinion about this though. Like Linder says free advice is worth what you paid for it.