I am still completely stock on an '07. Cold mornings I 1/2 choke until she's good and warm then unchoke. I will get a poof at shut down on occasion and once in a blue moon a backfire...but no decel backfiring. I will need to adjust *IDLE SPEED SCREW* settings again now that it's getting colder..  

BTW...I'm gettin' about 65mpg...

*Modified from my original posting. I apologize for the confusion caused by my lack of differentiation.

HTH(Hope This Helps)

False Illusion, I am trying to figure out what you mean by adjust settings again with cold weather coming. What adjustments do you mean? Are you the original owner.....if not is there any possibility that he/she made mods to the carb adj? I appreciate your help. It has given me encouragement that there is hope of being EPA legal and still have a good running bike.
Thanks, Dan

Anyone know if carb mods are legal for the owner to do? My bike mechanic said it was legal for me, but not for him.

My '06 S40 Boulevard has had half the white washer removed. That is the only mod I know of, but there may be more since I am not the original owner. I do know that it has a 150 main jet and the idle mixture screw is set at 1 1/2 turns out. Very few muffled back fires and almost no surging.

My Clymer Manual lists 3 carbs for the LS650 and S40. How do you know which carb came on the '07 S40 and which jets are stock? 145, 155 & 125 are the main jets shown in the Clymer Manual, but no mention of what year.

My bike runs great after halfing the white washer thickness, and gets about 57 mpg on the hiway. Most will think me crazy, but I would rather be legal if possible. I would not know which carb to purchase or what jets to replace or their size in the carb on the bike. Is there much exhaust emission difference made by raising the needle by as much as half the washer thickness? What about 145 to 150 main jet?

The Suzuki Dealer in Tifton Georgia said they have not had any returns for surging or back firing on these 650s for about 4 years the parts man has been there yet many on this forum modify the carb to prevent this behavior.

Thanks, Dan

Ebikerman wrote on 10/05/09 at 07:15:18:

Stock '05 had a 145 main, and it's unlikely they'd go richer on a later model.

Quote:

Dude. You would be an absolute fool to buy a new carb, or even any stock carb parts to bring yours back to factory specs, when your bike runs well, you're happy with the performance, and it gets 57mpg (!)

No bureaucrat is ever going to dig into your carb and find your dirty little secret, ooh the white spacer is only half as thick as it should be.. busted!  

Think of the environmental costs associated with junking the engine prematurely and building a replacement, because the mixture was off due to legal requirements.  Stupid laws should be broken and it's your patriotic duty to break them, IMO.  

Quote:

Right, because everybody knows it's far easier to turn a screw than go back to the dealer just to listen to a bunch of hemming and hawing about how they can't do anything because their hands are tied legally.  That's for warranty work, though.  Go to a Harley dealer and plunk down the money to convert to Screamin' Eagle gear and they're all "Sir, yes sir! Competition use-only parts coming right up!"

Boule'tard, You are right in what you say. No one will know my dirty little secret. However, honesty is very attractive to me in all aspects of life. If I will be dishonest in one place, I will be dishonest in others. My guideing light would be distorted toward selfishness. Who is my guide...Jesus Christ. My next dishonest moment might include you. Since I tend to walk the straight line, you are safe in all respects from me. Please don't be offended by my honesty and I do appreciate the effort and information you made to help me. That in itself is a good sign....Thanks, Dan

False Illusion wrote on 10/05/09 at 06:41:41:

How can you be completely stock and yet able to adjust settings.
Completely stock means you can't adjust any settings.
And its just amazing that you're getting better mpg than anyone.
And you're post says nothing about how perfectly well it runs,....if it is completely stock.

My 07 was completely stock, and it was ok,.....but it was not running correctly at intermedeiate speeds, so I fixed it w/ the spacer mod.

My bro has the same bike, and is completely stock. His runs exactly the same way, but he is ok w/ it that way. You don't have to mod a new bike, but if you want it to run correctly, you'll probably have too.

BTW, we both get 45-50 mpg, and both stock bikes afterfire on deceleration, and they both go "poof" when they shut down.

My '06 is completely stock and I can get it to backfire when I use engine braking when I'm coming down an exit ramp and I haul in the clutch.  It's worse on 90+ degree days, but I can pretty much do it all the time.  I also usually get a tiny poof on shutdown.

I don't seem to get any surges and I seem to have plenty of power and no overheating issues.

The only two things that I've done are was for the first 2500 miles or so I ran nothing but super unleaded in it and I turned the idle screw (the one on the left side of the carb) in about 1/4 turn since it seemed the idle was a tad low after the 600 mile service.

I'm getting between 55 and 60 mpg on a commute loop that's about 15% interstate and 85% surface streets.