Is that a belt drive? I've only seen two for sale here ever, probably more about, I'd read differing reviews. It may an have been one, as one was a shaft drive so it may have been something else.
I've seen a few different Suzuki cruiser like styles for sale from time to time, I'll have to keep an eye out for what I like that fits the bill. I'd take a liking to the Yamaha 535 but read it had its own particular problems.

Yes.The S40 (Savage) is single cylinder (Thumper) belt drive. :)

Added info on the 50 series. They all have a drive shaft from 2005 and up. All have Fuel Injection except for the S-50 which is a carbed bike.

I've seen an S40, tempted to replace my GZ, how much are belts commonly? Easily available, possibly online? My concern is its much older than my GZ which is running fine.
Similarly mechanically simple? Being older its possible its had more chances to have damage and wear even though the mileage is lower than its age would suggest, the condition doesnt seem near me even though it is old enough too, I'm tempted to permission to look at it and maybe keep my gz with the view to selling it. Yet to see the bike in person, just missed another very clean Suzuki of another model.

Belts are readily available & last much longer than a chain & very little maintenance. :) ;)

A belt is a lot cleaner too.

A few years ago I spent a fair bit of time lurking on a Savage650/S-40 forum. The bike has a large following of riders who just love the thumper. The bike has not changed a lot over the years.............just like the GZ itself. Suzuki has had the sense to keep them simple to own and maintain.

Top Speed
 

I have gotten my 2009 GZ250 up to 75 mph on a relatively level roadway with little or no wind. I weigh in at 170 lbs. and use 87 octane gas. I live at an altitude of 2100 feet above sea level and single digit humidity fyi.

Don't do that. A GZ will not be happy for long at that speed. Yeah, I know we all have to find out at one time or another. Lynda had her GZ up to 80 mph for a short stretch on the Canadian prairies. The bike sounded very angry and settled down nicely at 60 mph.

Like you said, you just have to know. I use my bike primarily as a commuter and usually keep it under 65 miles per hour. Mostly at 45mph.

Did that once with a car. Dang it was fast. Never did find out how fast it was as 135 mph is really scary and more than enough. Got arrested goofin off with that car.