Research,S-40 Backfiring
 

I am compiling information regarding the backfire problem with the S-40 Savage/Boulevard. Any information would be greatly appreciated. I need websites and hard evidence not just chat regarding this problem. This backfiring problem could be fixed properly without decreasing the horsepower and the handing of the bike. Suzuki chose the less expensive way to meet E.P.A. emmision standards. I have ask a consumer recall group to study this problem.Your help may force Suzuki to repair your bike old or new.( This is not a class action suit) This is only a method to jointly compile information that the dealer and manufacturer doesn't want you, the consumer to know. Thank You.

RE: Research,S-40 Backfiring
 

i also have an S40 and have dealt with the backfiring issue. the dealer said it was due to unfired gases being ignited in the pipes/muffler by glowing carbon residue in side the pipes. his sugestions were to adjust the air/fuel mix and use a higher octane of fuel. it still does it periodicly.
is this the only way to compile the info to help rectify the problem???
i love the bike and would like to correct the problem!
thanks special ed

RE: Research,S-40 Backfiring
 

My S83 is a month old with less than 1000mi has developed a backfire. Quite annoying when it occurs.

RE: Research,S-40 Backfiring
 

Getting back to your Savage 650, Coney, here's how we can specifically cure its problem. We need to richen those two areas of the curburetion curve that are factory set on the ridiculous side of leanness. Remove the diaphragm slide from the carburetor and look down inside its bore. Two small screws hold a plate over the slide needle.
Removing the plate, you'll see a small, white plastic spacer with a hole through it sitting on top of the needle. Throw that spacer away and reinstall the plate. A spring under the needle clip will now push the needle up to the plate occupying the space vacated by the white spacer. The distance that the needle has been 'lifted' is the thickness of the discarded spacer - and that's ideal. With the needle raised, more fuel will flow by it, meeting the actual needs of midrange running.
We can also fatten up the low end of your bike's carburetor by turning out the low-speed mixture screw. To gain access to this screw, you'll need to drill out the brass plug pressed in over it and yank it out with a sheet-metal screw attached to a slide hammer. You'll find that plug up high on the right side of the carb about where the mouth enters the carburetor. Usually Suzuki applies a splash of white paint over the brass plug so that it's immediately noticeable. With the engine warmed up and idling, turn the mixture screw out incrementally until you achieve the highest idle. There will be no doubt in your mind that you're making progress because the idle will come up and sound stronger. At this point, turn the idle adjuster knob out and bring the idle back down to a leisurely gait.
Just these two, relatively simple adjustments will not only eliminate the backfire, they will make an amazing improvement in throttle response and driveability. http://www.islandnet.com/~brclarke/ls650.htm

RE: Research,S-40 Backfiring
 

I've previously owned a S-50 but have now sold it now own a S-83 (2006). Both

bikes backfire once or twice during say a 1 Hr. cruise. This only happens when

downshifting from 3rd to 2nd gear; otherwise I like both bikes except perhaps

for the squealing brakes which seems to be a common problem.

RE: Research,S-40 Backfiring
 

I own a 98 Marauder and it also backfires, mine is running too rich. The problem started suddenly after it blew main fuse

So what's going on with these bikes is... a lean decel pop ? I've seen that on mx 4 strokes. What woof said makes sense , If you raise a carb needle and turn the fuel screw out ya richen both circuits. My questions are , does Suzuki frown on these kind of adjustments and , will it affect warranty ? My bike is under warranty for a year . thanks


Upon further reading , it seems the needle is not adjustable ? The bikes I'm used to have 5 slots on the needle so you can put the clip where ya need it? If this carb needle on the s40 has only 1 slot and a spacer on top of the clip....can you put the spacer under the clip to raise the needle?
I need to see a parts diagram on this carb to understand the design I guess.

I spoke to the Suzuki dealer I bought my bike from . I was told it's just the nature of the beast . They've tried many things for the annoying symptoms. Why should I 2nd guess factory r & d lol .The bike may be epa leanish but not dangerously so . Any bike can be made to run better , I've been in many 2 and 4 stroke carbs , making adjustments for years , oh well ...guess I won't mess with it . Basically I got the company line . ah...I still like the bike and it runs well , I just think what they say is funny .