Another great example of how "Harley" is going to shoot themselves in the foot. Some great "stealership" service there. They might as well have told you to take the bike and shove it up your butt. The backfiring out the carb is from too lean a mixture, which is common especially on the 06's. You need to get a manual, or do some reading on this forum, and re-jet the carb, and remove the plug that allows you access to the idle "mixture" needle. Then when you get it right, tell that "stealership" to shove it. On my 06 883, I'm running a 180 high, and a 48 low jet, and the idle mixture needle is out about 2 turns. Boy that pisses me off. I'll bet you would have got better service from a rice burner dealership.[:@]

 

no, my idle screw is on TOP of the carb on the right-hand side of the carb, just behind the breather cover... I can get to it with a long screwdriver without having to take anything else off... I'm thinking the mixture screw is on the bottom facing down

 

My bad - the idle screw is the only adjustment one you can get to outside the carb so I thought you were referring to that. The idle MIXTURE screw is indeed on the bottom of the carb behind the float bowl - it's up above the plug you have to drill out (unless it was drilled out before). You need a thin, narrow flat blade screwdriver to do the trick. P.S. Do NOT unscrew the slow jet (which you can't get to unless you take off the float bowl anyway)!

 

The slow mixture screw on mine is located on the top of the carb to the right of the idle screw, Keihin model 77' Sporty. Iam sure they are totally different on the evo's newer sportsters.

 

Man, how happy I am to feel that I am not alone with this problem of "running too lean". Mine is also a 06 883.
In order to avoid those carb problem I have to use enricher ****, and I think way too much. Otherwise it farts in the middle of the traffic or especially at intersections when I slow down. Man that pisses me off.
When the engine is warm, they it is OK.
I told the dealership twice, he say I have to use the EK longer, but I am sure it will foil the plugs. So what can I do?!!!

 

Its running too lean. Rejet with a 45 idle. Get rid of that 42. Also rich up the idle screw. It probably takes a while to warm up as well? This will fix both of those problems.

 

Thanks burnie,

Since I am incompetent in working on my bike, I will print this post and stick it to the dealers face....

Everytime I explain the trouble i am having, the mechanics look at me as if I dunno how to start and ride a bike![:@]

Again THANKS.

 

I've got the same problem with my 06 Custom. It's had the carb farts since day one.

At 1000 miles I added the SE II pipes and also the High Flow Air kit. Then had the dealer re-jet for me duing the 1k service.

The farts are no more frequent than before, but I now get them on occasion when I start rolling out into traffic from a stop. Took it back to the dealer yesterday, they "up'd" the idle a bit and enrichen the mix slightly (or they say they did). I cant tell they did anything. On the way home, it farted leaving a red light!

Looking at the pic above, and I am being dumb here, can I enrichen more by adjusting that idle mixture screw shown in the pic?? I can see it without taking the carb bowl off.

If so, I assume screwing it inward (clockwise) will enrich the mixture a bit??? Would this help, or am I totally off base here?

thanks!

 

Remember, every bike is different. 883 vs. 1200, altitude, temp, pipes, air cleaner and on and on. You have to figure out what is right for your bike. Late model Sportsters, when set at the factory are "leaned out to the max" so they meet EPA guidelines. You may need to adjust the idle mixture just to get to run right on a stock bike. If you change the air cleaner or pipes, you'll have to change the jets and the idle mixture.

AZFlyingDiver's picture (earlier in this thread) is great, so refer to it.

[IMG]local://upfiles/10560/C4F206B7813D459A9FB8C2C8A3C49078.jpg[/IMG]

There are three different things to adjust (probably more) when trying to get your mixture right. Since the bikes come from the factory "leaned out to the max" and most of what you'll change (air cleaner, pipes, etc) just makes the mixture leaner, we'll assume that you want to make the mixture richer.

1. For problems below 1/8 throttle, adjust the idle mixture screw.

Symptoms are; carb farts when pulling away from a full stop, excessive popping (backfire through exhaust) when the throttle is closed and you are letting the engine slow you down, lots of carb farts when the bike is cold (be careful - you don't want to tune for a cold bike).

Use a fairly small straight blade screwdriver to adjust the idle mixture screw. I'm assuming that you have already removed (drilled out) the plug covering the idle mixture screw. Clockwise "in" leans the mixture (less fuel). Counter-clockwise "out" richens the mixture (more fuel). Be very gentle with the idle mixture screw, it's OK to close it all the way but "forcing it" will damage the needle seat. Make sure to find out "where you are starting from" on the idle mixture. Before you change anything, count the number of turns "in" until the idle mixture screw is fully closed. An 1/8 of a turn can make a difference.

So now that you know "where you started from" down to an 1/8 of a turn, you ready to make a change. There are two methods for adjusting the idle mixture.

The first is to make small changes and test drive the bike in between. Open the idle mixture screw to "where you started from". Now open it counter-clockwise "out" 1/8 to 1/4 turn more. Ride the bike. You may need to richen the mixture more but test drive the bike after every 1/8 to 1/4 turn adjustment.

The second method is to adjust the idle mixture screw while the bike is idling. Get the bike completely warmed-up. Turn the idle mixture screw (slowly) clockwise "in" until the mixture is so lean that the engine starts to stumble or the idle speed increases. Now, turn the idle mixture screw (slowly) counter-clockwise "out" (count the number of turns) until the mixture gets so rich that the engine stumbles. Now set the idle mixture half way in-between. There is a detailed description in the www.sportster.org tech tips.

2. For problems between 1/8 throttle and 3/4 throttle, change the size of the slow / pilot jet.

3. For problems between 3/4 throttle and full throttle, change the size of the main jet.

Here is a table to use as a guideline for rejetting the pilot and main jets:

..........................................SE air cleaner
...............................Stock....OR SE mufflers.....BOTH
883.......................#42/160......#42/165.........#45/170
1200.....................#45/170......#45/175.........#48/180
1200 Sport/Intn'l.....#45/190......#45/195.........#48/200

 

coolnight,
Thanks for all the info! I'll give this a shot and see how it goes tomorrow. All my problems are below 1/8 throttle and/or coming out of a stop, so I'll start adjusting the idle mix screw slowly counter clockwise after I find my start point.