does kawasaki make A air mono shock for the vulcan 800?????

Not really familiar with your ride but is this how you change the load capacity on your bike. Nitrogen charged shocks have a much quicker reaction time and are usually alot more durable than air filled shocks is why most mono shocks are gas filled. Shock builders will be able to provide you with specs online and then it should be just a matter of finding a air shock with the same attachment points. Btw any small bikeshop with a decent metal fabricator will be able to change your shocks but it might be pricey. Ride safe!!

Thank you ill look in to it.