For the engine breather you can get a small K&N which fits - check their website. I had one on mine. Or you could just have the breather hose go down behind the swingarm.
We never had that air ssysem up here in Canada so I have no direct experience with it but I have seen many posts where guys just connected a hose from one side to the other like you said. The other way seems to be to buy block off plates for each side or buy a Canadian head.
1980 kz750E1, Delkevic exhaust
