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evo stuttering under acceleration

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Old Jul 4, 2014 | 11:15 AM
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Question evo stuttering under acceleration

Hey guys, new to the forum, looking for some help. I just bought a 1988 fxstc. It rode great for about 50 miles and then it started cutting out while accelerating. It really bogs down and gets real "choppy". It seems like a fuel/air problem but I'm not sure. I changed the plugs, drained the tanks, cleaned the petcock, cleaned the carb, rebuilt the accelerator pump, checked the ground...now I'm out of ideas. Does anyone have any suggestions on where I can go from here? It's got the S&S super E carb on it by the way. Any help would be appreciated.
 
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Old Jul 4, 2014 | 12:08 PM
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How are the seals on the carburetor's manifold? Try and spray some carb cleaner with the bike idling and monitor for rpm changes. Was the bike sitting a while? Get some more posts and post a video.
Welcome from Massachusetts!
Tom
 
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Old Jul 4, 2014 | 12:37 PM
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Default Shutter?

What speeds, gear and rpm, also is it chain or belt primary.
 
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Old Jul 4, 2014 | 01:29 PM
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The seals may be the issue. I sprayed some carb cleaner on the manifold and the bike almost stalled. I will try replacing them and hope that solved it. I'm not sure how long the bike sat before I got it. It has a belt primary. As far as speed, rpm , gear... it doesn't matter what speed or gear, more so the rpm. I don't have a tach so I don't know the exact rpm, but it runs relatively ok at low rpm. If I slowly roll on the throttle and up shift early, it doesn't act up too bad, but as soon as I try to accelerate gets real choppy. It actually feels like one cylinder is dropping out and coming back intermittenly. Like I'm riding at half power with short bursts of full power. I guess i will try to replace the gaskets and see where that gets me. Thanks for the responses and the welcome.
 
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Old Jul 4, 2014 | 01:53 PM
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Sounds like you need seals, but that may not completely solve your problems.
What condition are the plug wires in? The coil's plug wire terminals?
 
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Old Jul 4, 2014 | 02:03 PM
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Accelerator pump adj..??
 
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Old Jul 4, 2014 | 02:03 PM
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The wires are all in good condition and look like they're relatively new. I hope it's not an electrical issue. I was really hoping to get some riding in on this beautiful holiday weekend but it looks like I'll be turning wrenches instead.
 
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Old Jul 6, 2014 | 01:00 PM
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Let us know what it was.
 
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Old Aug 22, 2014 | 01:16 PM
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it turns out the problem was the ignition coil. I replaced that and the bike is running like a champ now. Thanks everyone for the input.
 
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Old Aug 22, 2014 | 05:19 PM
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Default champ

Originally Posted by porter011
it turns out the problem was the ignition coil. I replaced that and the bike is running like a champ now. Thanks everyone for the input.
She is 28 years old now and as a newly purchased bike ., i would definately go over it from stem to stern according to your manuals procedures .
If you take the time to do this you will have more piece of mind on long hauls etc. Congratulations on your purchase .
 
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