Hello,

I am a new owner of a 2013 Suzuki S40 and have had a tremendous trouble with backfiring.  I have been told by the dealership and Suzuki corporate that this is normal for this bike.  Can someone provide some insight into this and if I should expect backfiring of this bike?

And, does it go away or is there a way to minimize it.

For reference, I am experience backfiring any time I come off the throttle or shut off the engine.

Thanks.

My 2013 did for the first couple hundred miles and now it does it very rarely (less than once per 100 miles).  I haven't made any modifications to anything that would affect this.

JenRides wrote on 08/22/13 at 11:05:33:


A change in your riding style can affect the frequency and loudness of the backfire.

If you want to make a lot of noise - rev the bike up to high rpm's in each gear and let the throttle snap closed between shifts....and coast downhill with the throttle completely closed.

If you want to ride and make a bit less noise, then as you shift..... gently roll off the throttle and don't close it completely....hold it open just a little bit.  When going down a hill or downshifting to a stop....keep the throttle open just a bit.  By not letting the throttle close completely you are keeping the fuel jets open just a bit, and eliminating the lean condition that occurs when you let the thottle close completely and shut off the fuel flow from the main and needle jets.

Adjusting the idle fuel screw can help some, and installing a #50 pilot jet in an otherwise stock bike with a 47.5 pilot jet can help.....but increasing above that will have an affect on fuel mileage.  The white spacer mod will make a bike that runs better.....and may also help to cut down the backfires as it will allow more fuel to flow out the needle jet on low throttle settings.