I just picked up a 2004 Savage on Friday afternoon.  I took it out for a short test ride and found it to be everything I wanted in a bike. Everything was great, until I rode it home.

As I was decelerating from the expressway, the backfired.  It sounded like an M-80 was going off behind me. To say the least, I was a bit startled.

I got to the exit ramp and verified that every time the engine spooled down from high rpm (higher than I had reached on my test ride), it would backfire.  Sometimes just a little puff and others the M-80 was back.

I called the dealer that I bought the bike from to schedule a service appointment but was told that the Savage is known to backfire (it's normal???) and there was nothing to worry about.

Well, I rode about 100 miles since then and every time I roll the throttle closed, it will either pop or bang (depending on how it feels, I guess).

I really thing I may have a partially blocked jet in the carb, as at certain throttle positions, I can feel the engine surging.  

Without getting too dirty, is there any way I can try to clean out the carb? Would it hurt if I were to mix in some STP fuel system cleaner with the gas?  Will that make any kind of difference?

Outside of that, is there anything else I could try without disassembling the gas tank and messing with the carb?

Like Sluggo said, it will pop when you let off the throttle at highway speed quickly.  I have learned to gently roll off the throttle when ever possible, and I don't get the pop as much, if any.  I used to get a little puff when I killed the ignition, but after my second scheduled check-up, it has gone away, or it may be just the change in seasons.  My S40 is an 06 model, and I live in South Mississippi.

I had a 2004 which I was able to tune (without re-jetting) to reduce the backfire condition to the point where was difficult to make it backfire even if I really tried, and it didn't exist in normal riding conditions. It was a matter of making sure everything was in adjustment mainly the idle adjustment (which as you read you will find requires you to remove a brass plug to get at the adjustment. My gas mileage also remained over 50 mpg overall with all kinds of riding.

If you don't want to do the work yourself, you will have to find a mechanic to assist you who is willing to say that it shouldn't be that way.

Since nobody specifically addressed your "surging" condition, I'll throw in 2 cents worth...

This is primarily due to a slightly lean condition in the mid-range.  It will be more pronounced in colder weather, and on a hot day when the bike has been worked hard it will probably go away completely.  It won't hurt anything to leave it that way, but you could perform the "white spacer mod" mentioned in the tech section to eradicate it.

Welcome, and enjoy the THUMP!

My 96 also had that shotgun blast backfire, sometimes it would do it 3 or 4 seconds after shut down too. After I changed to a HD turnout muffler and reset the idle mix screw (under that pull off brass cap on the right) it no longer has that huge backfire. It pops and snarls a bit between shifts but nothing like an M80 now.

Ok,

I did a bit of poking around and found that there are several possible causes for the shotgun blast, not the least of which could be an air leak caused by loose exhaust bolts.

So I went outside with a torque wrench in hand and yup, they were loose.  So was the muffler clamp (to the frame) as well as the front engine support bracket.

I torqued everything down to specs and started it up.  

Wow.  No more rattling!  I gave it some gas, no stumble and no backfire!  I may have figured this thing out.

Thanks to whoever posted all the bolt and nut torque specs in the Tech Data section.  When I get a chance, I'm going to go all over the bike, just to be sure...

got the bike on friday, and taking inexperienced passengers on tuesday.  be very very carefull.

i made mine a solo so i would not have to carry passengers.  in my history it's been the inexperienced passengers that have caused me the most trouble.  i even got sued by a relative for a minor fall that he caused by moving around while coming to a stop.  he broke his thumb when we fell, and acted like his hand had been chopped off.  needless to say we don't exhange christmas cards anymore.  

I tell my passengers to put there arms around my waist and lock them together.  Pretty much garanties them not moving around.  Tell the ones with long arms to walk.