Exactly! And you can see all of reasons for my hesitation. All I can say is that you need quality gaskets and seals and be ready to discover more issues as you go.
My main reason for the whole thing was the occasional cough - once or twice per hour when cold. Cleaning up the carb led to replacing all the seals and the vacuum slide, that led to changing the intake manifold seals too, that led to replacing the manifold itself. Can I for certain say that all that will fix that minute cough?
Be glad it was only a cough.
Just imagine exhaust issues and the colonoscopy.
Put it all back together with new intake manifold and James seals... And I did take my time.
The bike definitely runs differently now. There's noticeable flat spot on 2nd and 3rd gear - basically turning the throttle doesn't do anything and then it picks up at some point. Not sure if I'm explaining it right. No coughing tho at least so far.
Here's a pice of the intake before I closed it - does the black build up in the front cylinder signify former air leak?
I spoke too soon, after rebuilding the carb, and replacing the intake manifold and seals, also rejecting it to 45/170... She still coughs. Mostly when I take off on first gear. Kind of the same as before. But now, I don't think it's running smooth at low rpm.
Not convinced that the mixture and idle are properly set. Would that explain the sporadic cough at low rpm and/or not running as smooth?
I have had my S&S Super E on my bike well over 26 years now and I have never done anything to the carb except a gas filter and I have only used non-ethanol gas with a dash of Marvel Mystery Oil and Sta-bil mix always in the gas but I purchased the rebuild kit recently but the idea of me taking that old carb off is like going to the dentist, I know its time but I keep asking myself can't I go one more summer?
Yes, as I age I fall more on the side of the "if it ain't broke, don't fix it" perspective, against the usual wishes of my OCD.
This has been a long post, and I forget some of what you already did. Did you replace the vacuum slide? Is that operating correctly? Is the diaphragm part fully sealed with the cap? IIRC, they are a bit tricky sometimes to get fully seated. Just a thought about your mid range issue.
This has been a long post, and I forget some of what you already did. Did you replace the vacuum slide? Is that operating correctly? Is the diaphragm part fully sealed with the cap? IIRC, they are a bit tricky sometimes to get fully seated. Just a thought about your mid range issue.
John
Here's a summary of what I've done
2003 Sportster 883C
Cleaned the carburetor thoroughly
Replaced all the seals
Replaced the vacuum slide
Replaced jets to 45/170
Replaced manifold intake and seals
Replaced the spark plugs
Mixture screw set at 2.5 turns
The bike runs rough, especially at low rpm. It coughs. It starts and runs, no sputtering or misfiring but.. With single rider (me) it barely holds at 60mph: I have to run it a gear lower. It runs worse than what it was originally with all the oem parts after 20k miles....
Gents, I took your advice and I'm worse off. There's cost to it too. I'm lost. Any final advice would be much appreciated
All you can do is retrace the steps you've taken, and try again. It's obviously carb/intake related, there's nothing else wrong with the motor. Don't give up. I've had to pull carbs and go through them again many times working on friend's bikes. Sooner or later, you'll get it dialed in. Sounds to me like you might have a vacuum leak at the manifold. I know you hate to hear that, but... What was your procedure for installing the new seals and manifold? Dish soap? Red grease? You left it a bit loose till the carb was aligned, then gently tighten the bolts? You got the flanges correct?
There's something not right, you just need to find out what it is. I know you will. There's a reason mechanics charge $200 an hour today. Sometimes it's easy, and sometimes...
John
Last edited by John Harper; 08-30-2024 at 10:28 PM.
08-28-2024, 11:18 AM
