Twin Cam 88 Problem
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Stage II
Joined: Oct 2010
Posts: 2
Likes: 0
From: Borger Texas
Twin Cam 88 Problem
My 2003 FXDL started loosing speed and began miss firing under a load. I let off of the throttle and it idled perfectly each time. I gave it some gas and it bogged down and started miss firing again and then idled perfectly with no load once again. After awhile, it started running perfectly again as if I never had a problem and I took it to my dealer which they said they could not duplicate the problem and could not fix it. Last year, it did the same thing and blew an intake gasket. The problem, I thought, was cured by replacing the gasket and it has ran perfectly until last week. I bought a Harley code reader and I hope I can find the problem when it does it again. Has anyone had the same problem? And found the cure? I have almost 24K miles on the odometer.
You don't really need a Scanalyzer to read codes, but always handy to have. There is a code-read procedure onboard. It's primitive....reading/counting light-flashes.
Anyway: fuel delivery, fuel problem(water/Ethanol), something overheating in electrical-spark delivery, vacuum issue with carb or fuel filter.
Detective story.
Got a Harley SM?
Anyway: fuel delivery, fuel problem(water/Ethanol), something overheating in electrical-spark delivery, vacuum issue with carb or fuel filter.
Detective story.
Got a Harley SM?
Thread Starter
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Stage II
Joined: Oct 2010
Posts: 2
Likes: 0
From: Borger Texas
I topped off the tank after riding 50 miles and rode another 15 before it started cutting out. I was still on the same tank when it starting running good again. I wouldn't think it was the gas. Fuel delivery, maybe. Do you guys use any octane booster? Any other thoughts on what is happening to me?
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Ultimate HDF Member
Joined: May 2008
Posts: 6,642
Likes: 48
From: Ogden, UT
When was the last time you replaced your fuel filter? Certainly sounds like a fuel delivery issue.
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Tourer
Joined: Dec 2009
Posts: 406
Likes: 13
From: Langley, BC. Canada
I have a 2001 FXDWG with exactly the same problem. It is intermittent, so it obviously has nothing to do with water or quality of gas. It used to happen once or twice in 4000 miles, now it happens quite often with no consistency as far as frequency is concerned.
It really seems like a fuel delivery problem which can be caused by a vacuum problem because the fuel valve is operated by engine vacuum and the carb slide is operated by carb vacuum.
I have replaced the fuel valve 3 times. The first time it would run out of gas when holding it wide open for a length of time, like passing a car. Not good. There was a pinhole in the fuel valve diaphragm on that one. That change fixed that problem. No more problems until this intermittent thing surfaced last year. I just purchased a manual fuel valve and will install it soon. Hopefully that solves the problem. If it doesn't, I will be back in the same boat as you. Wondering what the hell it is. I have a new slide and diaphragm in the carb, so it isn't the slide diaghram. When it runs right it runs really sweet. No sense in taking it to a wrench, because if it ain't broke they can't fix it.
Like you, my bike always idles good and always runs good up to around 1/4 to 1/3 throttle and when the problem appears it acts like it is simply not getting enough fuel, beyond those throttle openings.
It isn't the Ignition Module because it happened with the stock Ignition Module and is still happening with the Dynatek Ignition Module I installed. I guess there is an outside chance it could be the coils, but I will only go there as a last resort. To the best of my knowledge coils aren't known for intermittent problems.
Let's hope someone comes to the rescue of both of us. I am sure it will be someone who experienced the same issue and solved it.
:-/
It really seems like a fuel delivery problem which can be caused by a vacuum problem because the fuel valve is operated by engine vacuum and the carb slide is operated by carb vacuum.
I have replaced the fuel valve 3 times. The first time it would run out of gas when holding it wide open for a length of time, like passing a car. Not good. There was a pinhole in the fuel valve diaphragm on that one. That change fixed that problem. No more problems until this intermittent thing surfaced last year. I just purchased a manual fuel valve and will install it soon. Hopefully that solves the problem. If it doesn't, I will be back in the same boat as you. Wondering what the hell it is. I have a new slide and diaphragm in the carb, so it isn't the slide diaghram. When it runs right it runs really sweet. No sense in taking it to a wrench, because if it ain't broke they can't fix it.
Like you, my bike always idles good and always runs good up to around 1/4 to 1/3 throttle and when the problem appears it acts like it is simply not getting enough fuel, beyond those throttle openings.
It isn't the Ignition Module because it happened with the stock Ignition Module and is still happening with the Dynatek Ignition Module I installed. I guess there is an outside chance it could be the coils, but I will only go there as a last resort. To the best of my knowledge coils aren't known for intermittent problems.
Let's hope someone comes to the rescue of both of us. I am sure it will be someone who experienced the same issue and solved it.
:-/
Outstanding HDF Member
Joined: Aug 2009
Posts: 2,938
Likes: 4
From: NC
Sounds like the ignition coils are on the way out. I would replace the coils with a known good set. Your coils are getting hot and losing spark which is usually apparent under a load when hot.
The intake gasket failure was a result of the misfire not the cause of the problem.
The intake gasket failure was a result of the misfire not the cause of the problem.