2006 1200 Custom backfiring

[murphdog]

When dealers "rejet" a carburetor, they generally put a Dynojet kit in it. This is what Harley sells and this is what the dealers use. The Dynojet kit instructions say not to replace the slow jet, so that's what gets done. Last I knew Sportsters still came with a 42 slow jet so they would pass emmissions, and, unless you live at 8,000 feet, this will cause the off idle problems you are having. Go buy a 45 slow jet, put it in yourself, adjust the idle mixture screw for best idle and your problem will most likely go away. There usually comes a time when it's just easier to spend a couple bucks and do something yourself rather than argue with an arrogant service writer at a dealership who will insist that they all do that, we can't find anything wrong, it does that because you changed this or that, yada, yada.

[al_huryn]

Hey Murphdog thank you I agree, one guy I was talking with said to go to a 48 jet and it would cure it. I bought the bike set up the way it is so I'm trying to decipher what was done thus far, I can only go on my salesman told me the bike was rejetted when the air cleaner and pipes were put on. I've been out of riding for a while so I'm kinda going on what I can remember and a good portion is from racing dirt bikes but as far as I can tell it's still the basics rule and work from there. I just had the feeling when the off idle issue was noticable to me where to look at least, I can do not all but a good amount of work myself so thank you again for at least reaffirming what I thought I knew. Again guys I will keep messing around with the bike and post, if it can help someone else then you all and myself, by proxy, have done what this site is all about, to help each other..Thank you from a new bike owner...Al

[sjohns]

Right after I bought my 2006 1200c, I put in a thundeslide. I had back fire symtoms until I readjusted the needle. I needed to move the ring up one slot if I remember right, it's been awhile. I use the 45 main jet that came with the stage one kit and use a 180 needle jet.

The only other time I had ignition problems was when using Valero gas out here in California. It made the bike "hiccup and sneeze". I stopped using the gas, and all is well.

These back fires make me think of a jetting problem. Also make sure the carb and intake are seated fully. You could be sucking air at the head where the intake connects.

[jat3]

I also have a 2006 sporty had the same problem i got so pissed at the dealer i bought a S&S carb and that cured it until the temp outside changed then it was back so i took my cv carb in and had the thunder slide kit put in it with a 48 180 jetting and have not had a problem unless i idle to long with the choke on

[smoke245]

KrustyC,

I noted that you say all harley's do not vibrate. I guess you are right? But I have a 2005 XL-1200 custom that since I bought it last year really vibrates. At idle my horn looks as if it is going to vibrate off, and the front end sits and dances at a stop light. I am running a 45 slow jet and I think an 88 main. I have the V&H air cleaner, and cycle shack slip ons. I have checked the plugs and they are the right color, so I do not think the problems lies with them. Any suggestions? Is it maybe the timing?

[KrustyTC]

What I meant by my statement smoke245 is that the dealers excuse that "all Sportsters do this" or "all Harley's vibrate that much" isn't a solution to the problem. If you don't think your bike is running right or are not happy with it's performance the dealer should do what it takes to make it right.

All Harley's do have some vibration, I know my 05 Super Glide does. But it shouldn't be excessive. I know if my feet vibrated off of the pegs every time I rode my bike I'd have it back to the dealer to see what was wrong. And I wouldn't just let them give me the "all Harley's do that" excuse just because they don't want to put the time and effort in to fix the issue.

I know my Dad's 04 1200 Custom vibrated quite a bit at idle. But smoothed out once he was on the move. You might want to bump your idle up a little bit to see if it smooths out some. Most shops tend to set the idle a little low. Do you have a problem keeping your feet on the pegs or are the mirrors so blurry you can't tell whats behind you? As long as it's fine while your riding I wouldn't worry too much about it. But if your bike is still under warranty make an appointment to have it looked at just for peace of mind.

later,
KrustyTC

[pirate50]

Originally Posted by smoke245

KrustyC,

I noted that you say all harley's do not vibrate. I guess you are right? But I have a 2005 XL-1200 custom that since I bought it last year really vibrates. At idle my horn looks as if it is going to vibrate off, and the front end sits and dances at a stop light. I am running a 45 slow jet and I think an 88 main. I have the V&H air cleaner, and cycle shack slip ons. I have checked the plugs and they are the right color, so I do not think the problems lies with them. Any suggestions? Is it maybe the timing?

Smoke, I would check the front motor mount bolts. My bet is that if your bike is vibrating that much, you have a loose bolt. The top bolts are easy to get to; the bottom more difficult. See if they are loose, torque 'em right and see if your bike doesn't smooth out.

Pirate

[claydbal]

can someone give Al JD's number? isnt he around philly?

[al_huryn]

I am in South Philly. I met another Harley guy that says the bike was not jetted properly after the previous owner did the mods. With all this crappy weather though I haven't had a chance to hook up with him to get the problem worked out. This issue is driving me nuts though, and the dealership is useless on it.

[Buddy Seat]

Most stealerships are useless you're biuying something.. Then you have their undivided attention..

I'm not a sporty guy, but I wrench on most ALL Hd's.

The new bikes come super-lean to pass EPA regs..Something like 14.5 parts air, to 1 part fuel.. So adding K&N or other hi-flow air filter kit will make things worse....Then add hi-perf pipes it gets Leaner yet.. Gotta match the carb to the improved breathing..

Any carb coughing is most times a sign of a LEAN condition.. Providing ya don't have any intake leaks..

I don't care for the dyno-jet kits they add too much fuel & can wash oil off the cylinder walls & actually shorten the top-end life span..

You need someone to get at your idle-mix screw & adjust it say 2.5 turns out to start, & add a 45 slow jet..or one size larger than what is in there. This should get you in the ball park..