If you use a 16" LTD wheel, there will be more room for a wider tire.( I've spooned on a 150.) With a stock swing arm, there isn't much room for more tire with a stock 18" rim. 130/140? 80/18. You'd need a wider swing arm also. Several outfits widen the stock rear wheels. If you go over to a spoked back wheel, you can easily convert to a wide rim. Many have adapted later, sport bike rims. You'd have to make up some spacers. And again, you'll need a wider swingarm and probably an off set front sprocket to keep it all aligned.
Only Kawasakis have a soul 1977 Kawi KZ1000 special 2000 Kawi ZRX1100
