I am considering buying either a Suzuki Boulevard S40 or the Kawasaki Vulcan 500.?

Or I will consider their predessors which are almost the same except for name changes. The Suzuki is a 650cc single cylinder air cooled engine. The Kawasaki is a 500cc twin water cooled. Will the method of cooling have an affect on the maintenance or length of life of the engines?

i say that unless you plan to ride long distance it doesnt matter that you have a radiator. i have rode trips up to 100 miles straight no stop in the middle of summer in the south with an air cooled two stroke street bike with no problems.

Yes. Water-cooled engines always last longer&make more consistent power. Of course they ar ealso slightly harder to maintain, but not much. Go with the Kawasaki.

Buy the Boulevard 50 Cruiser. Much nicer bike with water cooled engine.

I had the Suzuki single jug 650 (Savage). It was a good bike, but it lacked power at highway speeds. The Kawi 500 may give you a bit more since you have two jugs moving. If you want to avoid getting run over on the open road, consider something with a little more get up and go... I got a Kawi 1500 and love it. :)Good luck!

I'D GO WITH SUZUKI 650cc AIR COOLED, NO PROBLEMS WITH AIR COOLED, THEY BEEN ON THE ROADS FOR ABOUT 100 YEARS, MINE IS....AND SEVERAL I HAD WAS, IM ON MY 35th BIKE....TAKE A PEAK AT THE YAMAHA 650cc, THEY ARE AIR COOLED AND SHAFT DRIVE.....THIS IS FREE TOO....BELT AND CHAIN DRIVEN BIKES NEEDS AJUSTMENTS- SHAFT DRIVE DONT.....I HAVE A BELT DRIVEN BIKE ALSO, BUT I'D NEVER HAVE A CHAIN DRIVEN STREET BIKE......IT SLING THAT PJ-1 CHAIN LUDE EVERY WHERE.....HOPE THIS HELED YA SOME.... BIKE ON .. BIKE SAFE