I just bought a New 2015 S 40 ..... ok first off I put fresh gas in it and seafoam. IT is slightly backfiring. my question is it sat all winter at this dealers shop.. should it be doing this. it is a new bike only had 2 miles on it...i rode i for just 3 miles around my Apartment complex.
  is this a normal thing for these bikes..its not a loud backfire.. but it is doing it. any help appreciated ????? Thanks Pam

When is it backfiring?
Changing gears?
Coming to a stop?
Shutting off?

First, don't panic.
It's just a big single cylinder engine and is prone to backfiring.
Some of it can be controlled by how you use the throttle. Letting it slam shut can make it do it. Another common cause is a slight leak in the exhaust. The connection between muffler and header may not be right. The seal where the header goes into the head may be a bit loose. Tightening those requires a gentle hand and the understanding that, eventually, they will need to be snugged again. Or, you can decide you're gonna tighten them so they never shake loose again, at which time you'll certainly twist something off. Only adjust those when the engine is cold.
As mentioned above, there is a brass plug over an adjustment set at the factory. The EPA has forced Suzuki to jet the bike leaner than when they first came out some thirty years ago. The idle air adjustment is rarely set for optimal performance and can, like exhaust system leaks, cause backfiring.
We have seen the result of taking a new bike to the dealership.
I don't recommend it.

We've seen engines destroyed by professional mechanics who installed the oil filter backwards. The list goes on.
The expertise of the people here who have been keeping these bikes alive dwarfs what they know in a dealership. They work on a wide range of products and the Savage is relatively uncommon and not something that the mechanics are all excited about working on. So, the least capable mechanic gets the simplest jobs. Your bike.

Congrats on the new purchase! Read through the tech section thoroughly for answers to most of your questions.  

What's your mechanicing experience, and or DIY experience.

Hi, Pam,

I bought a new 2015 S40, too (first brand new bike in 30 years) in the red metalflake. I was startled by the backfire first time I shut the throttle quickly at 50 mph -- thought I'd blown the muffler off! lol

Per advice I read here, I'm a bit gentler with the throttle. Also, at the end of a ride,  letting the bike idle for about 20 seconds before turning the key off reduces the xhut-down backfire.

Hey, there, "Rat"...

Alas, in my neighborhood a loud backfire might just be mistaken for gunfire....and possibly elliciting an Unwelcome Response. Gotta love livin' in the Big City.

to Dave,,, Thank you ..appreciate you helping me.