how do I get it to stop backfiring thru the carb?

Delaware 1200 Custom · #1 04-10-2006, 11:21 AM

I have an 06 Sportster... just took it in for the first / complimentary service, and told them to look at the carb... all they said was "is this your first Harley? that's just a Sportster for you"

I told htme how bad it was, and how dangerous it is... I mean it's cut out on me several times trying to pull out into traffic and pulling across intersections...

the dealer obviously won't do anything.... any tips? can I try playing with the fuel/air mixture screw? do I need to take it to a REAL mechanic? or is this really the way it's supposed to run?

thanks

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Terry1955 · #2 04-10-2006, 11:24 AM

If your bike is under warranty you need to raise hell until it is fixed. It is probably running lean and if you take it to another dealer and explain what's going on they should be able to fix it. You may get a little of this when the bike first starts or when it is cold but a properly tuned bike should not be backfiring through the carb/breather.

Shovelhead77 · #3 04-10-2006, 01:51 PM

Sounds like it's running lean, You could try the the slow jet screw, turn it all the way down till it seats, Then turn it out 7/8 of a turn, ( a little more than 3/4) If it's still doing it, Like Terry said, take it to another dealer and tell them what it's doing. They should be able to tell you whats wrong, and fix it.

Delaware 1200 Custom · #4 04-10-2006, 02:00 PM

I called a different dealer... he said to try changing the plugs, they could be fouled...
he told me that the choke pull-out knob isn't really a choke (which I didn't know) that it's just an "enricher" and that it's easy to foul the plugs on the Sportsters...

do you guys agree with that?

he also gave me tips for starting it from now on... using the "enricher" as little as possible

Delaware 1200 Custom · #5 04-10-2006, 02:03 PM

Quote:

ORIGINAL: Shovelhead77

Sounds like it's running lean, You could try the the slow jet screw, turn it all the way down till it seats, Then turn it out 7/8 of a turn, ( a little more than 3/4) If it's still doing it, Like Terry said, take it to another dealer and tell them what it's doing. They should be able to tell you whats wrong, and fix it.

is that the screw on the bottom of the carb, just behind the intake?
the screw head is facing straight down, so your screwdriver would be pointing straight up when adjusting it.... is that the right one?

JohnK/Pa · #6 04-10-2006, 02:45 PM

The best thing you can do is look in the DIY help forum under the fuel/carb related and you'll find some great articles there with pics. I have my 1200 jetted to a 45 slow and a 170 main and a thin needle and I run the screw turned out to about 2 turns. Read the jetting sections and you'll learn alot.

Otter · #7 04-10-2006, 02:53 PM

Sounds lean and sounds like your dealer is not helping very much (at all). Your sporty is NOT supposed to run like that. Take it in to the dealer you purchased it from and tell them to fix the damn thing. If it is plugs - then fix it! It should be a peice of cake for those certified knuclke busters, right! Dont let them give you (more) crap. If you have not modified the bike and it's new - they need to step up and fix it!

jerseyjeff62 · #8 04-10-2006, 03:29 PM

Quote:

ORIGINAL: Delaware 1200 Custom

I have an 06 Sportster... just took it in for the first / complimentary service, and told them to look at the carb... all they said was "is this your first Harley? that's just a Sportster for you"

I told htme how bad it was, and how dangerous it is... I mean it's cut out on me several times trying to pull out into traffic and pulling across intersections...

the dealer obviously won't do anything.... any tips? can I try playing with the fuel/air mixture screw? do I need to take it to a REAL mechanic? or is this really the way it's supposed to run?

thanks

did you change your pipes and a/c?spray some wd-40 around the manifold by the heads while running.if the idle changes you have a leak.that also would cause it too run lean.that what i did.change out the intake seals and the rear seal was leaking. if you can find the leak with the wd 40 and you can show you dealer it leaking then they should cover you.

AZFlyingDiver · #9 04-10-2006, 06:48 PM

Quote:

is that the screw on the bottom of the carb, just behind the intake?
the screw head is facing straight down, so your screwdriver would be pointing straight up when adjusting it.... is that the right one?

nope - that screw is to adjust the idle RPM itself (it's not the idle mixture screw).
best suggestion is to get the service manual (available at the dealer) - detailed info including diagrams for crab stuff is included...

AZFlyingDiver · #10 04-10-2006, 06:53 PM

Quote:

ORIGINAL: Delaware 1200 Custom

I called a different dealer... he said to try changing the plugs, they could be fouled...
he told me that the choke pull-out knob isn't really a choke (which I didn't know) that it's just an "enricher" and that it's easy to foul the plugs on the Sportsters...

do you guys agree with that?

he also gave me tips for starting it from now on... using the "enricher" as little as possible

The enrichener knob is indeed the carb's choke. And you can foul the plugs if you fail to use the enrichener knob correctly. Usual best practice is to pull it out fully when starting a cold engine, start the bike, let it run about 30 sec., push it in part way, run/ride for a mile or so, push it in the rest of the way. No need to use it to start if the engine is warm. Over-use will foul the plugs over time.