My 1200 had the Stage 1 AC on it when I got it. I have put 4,000 miles on it and changed from drilled out stock mufflers to Screamin Eagle II mufflers. It had 158 miles on it when I got it. It was owned by the wife of a local Harley mechanic. He had done the ACupgrade and rejetting of the crab.

I had the plugs foul out 2 times last year. I was told that I do not ride aggressive enough. Has anyone else had problems with fouling plugs on their Sportster or does this sound like the right answer to the problem? I did a search for plug fouling but did not come up with any answers.

Thanks for your input.

Cheryl

 

You would really need to provide more information as to the type of 'fouling' on the plugs.

The two most common types are oil getting to the plug, or overly rich running conditions.

You shouldn't have to ride 'aggressive' to keep the plugs from fouling if the bike is tuned properly. I don't race any of my Harley's, and I don't remember the last time I've even opened a throttle past the halfway mark. None of them have a fouling plug problem.

If you have oil fouling it is probably caused by bad seals, which isn't that difficult to correct.

But one of the main causes of 'too rich' fouling is overuse of the enhancer/choke. People seem to love pulling out the choke and then leaving it on for too long of a period. All this does is dump excessive fuel into the cylinders. I use the choke as little as possible, even in sub-freezing conditions.

Also, something I will never understand is people rejetting their bikes when they modify either the intake air flow or exhaust flow without hooking on some gauges to check for the correct air/fuel mixture. You can't just automatically throw in different jets assuming that is what needs to be done.

When we installed higher performance Screamin' Eagle cams in my 2005 1200C, and increased the intake and exhaust flow, the local 'carb guru' hooked up a gauge to optimize the a/f ratio throughout the operating range. Very little adjustment needed to be made to the carb, and if I would have changed the jetting to some recommendations I see on the various Forums it would have been running way rich.

You can't use a 'seat of the pants' dyno to determine the correct jetting for a specific bike. The only way to set the correct air/fuel ratio is to either put the bike on a dyno, or hook up gauges to get an accurate a/f mixture readout.

Anyway, sorry 'bout the rant. LoL..

 

When I bought my bike, the head service tech told me during the walk around that the main reason plugs get fouled is running it with the enricher pulled out. (He told me he strongly disagreed with H-D's recommended warm up procedure.) He told me to pull the enricher out and fire it up and only let it run a bit with the enricher on. He told me it was better to use the throttle and then lockthe throttle rolled on a little bitand turn the enricher off and let it warm up that way.

 

I have to agree with OFG...

Because most techs get paid by the book... they tend to do what has worked for them in the past... but it's not the proper way it should be done...

I too have never foulded a plug on a Harley... knock on wood (using head as block)... but that is not to say it doesn't happen and could happen to any of us at any time...

I'd read the plugs... if there is oil residue on them... I'd use my warranty... if they are black, deep charcoal... I'd say you're running to rich and may be a jet problem (too big)...

Running the choke/enrichner too long at warm-upwill give you problems also...

I actually run a hotter plug in my front cylinder than I do the rear... because the exhaust is telling me my front cylinder is running a little richer... works for me...

Anyway... hope these comments help...

Charlie D.

 

OFG & Charlie, Well heres the scoop! The first time I noticed it was on the way to a dealer. I had a noticeable loss of power and black smoke from the rear muffler. When we got there they pulled the rear pipe, muffler was "wet" inside. The head exhaust port was clean and dry. Pulled the plugs and they looked "blackish".The mechanic ran it down the road a mile or so and came back and said it ran good for him. We put new plugs in just because they are cheap. Ran good for a few weeks and did about the same again.

From what you said I believe I am using the choke to much. I have been doing what the guy that sold it to me said. Starting with full choke, ride about a mile, then half choke for about another mile, then off. The second time I had started it and only gone a little ways and shut it off. Then when I started it and rode some more it fouled.

From reading your reply this seems to be the problem either to much choke or to rich. Most of the time there has been no trouble so I am leaning on the choke use being the problem. Sound right to you guys?

Thanks for the replies I do appreciate it.

Cheryl

 

Any chance you can find what jets are in there ? You're fuel/air mixture is too rich which can be caused by air restriction (probably not) or too much fuel (jets too large). Like OFG said, the Harley or Indy shop can use an exhaust analyzer too confirm it. My factory jets were too large which caused my plugs to soot up. I didn't realize how bad it was until I did the 1200 conversion and saw how much carbon had built up on the heads and pistons. No way should you have black (or any other color) smoke coming from your exhaust. It needs to be fixed ASAP.

 

I agree with the above posts. I doubt your use of the enrichener is the problem. The stock jets on a 1200 are typically 45 low & 180 high. A stage 1 rejet usually takes the jets to 48 low & 190 or 195 high. Either verify your jet size or have the A/F mixture analized or dyno the scoot. Don't bank of the fact that the previous owners hubby did it right. Also if you live at a higher altitude >3000 ft the jet size may need to be reduced some. You might also try removing the A/C and look into the carb throat and verify that the enrichiner butterfly is open fully when the enrichener **** is pushed in.

 

Well the only time there was black smoke was when the rear plug was fouled. After the new plug was installed there was no smoke. I am going to have some one do an air/fuel check on it and see what that tells us. But it will have to wait for warm weather. I can ask the guy that did the carb exactly what he did when installing the Stage 1 AC.

Thanks everyone for all your help! I want warm weather so I can ride again [:@]

Cheryl

 

Very well could be...use it sparingly and see if that helps... Anyway... it only take a little bit longer to get going using less choke...

 

Stock slow jet on a rubbermount 1200 is 42 not 45. 45 is stock on the big twins. On a sporty you usually end up with 45/180.