S&S Super E quandry

[midwestcowboy]

Good Morning to All:
                              I bought a '92 Heritage with an S&S Super E last year, rebuilt it over the winter..including the carb. I logged alot of miles over the summer and all was purring along. Recently the ol gal has started running rough, hard to start, periodically backfiring through the exhaust, and the plugs indicated I'm running on the rich side.
                              I'm assuming the carb was jetted right from the previous owner ( and initially all ran good with good color on the plugs). I've checked my electrical connections, intake and exhaust for leaks, new plug wires, and went through the procedures on the set-up sheet.
                              I'm an old Panhead rider, and am not familiar with the EVO electrics. could my problems stem from something electrical? At cruising speed she runs like a top, no lag when I juice the throttle, although at idle theres lag when I gas it, and at 40mph I can here popping through the pipes ( V&H long pipes)
                              From what I've read, I can't expect "optimum" performance with the long pipes, but I'm baffled as to why the ol gal has gone from running great to poor. Thanks,and Happy Trails     

[Buffalo]

 The first things I would check would be inside  the float bowl. Shut off the fuel, drop the bowl, look to see if the intermediate jet, and the main jet are secure (tight). Check the needle and seat, if its older than say 7years, I'd replace it.
If the fuel is older than 3 months, drain and flush and refill. Check the bowl for a varnish like buildup. If any exists I'd use Seafoam, soaking every part for at least 24 hours. Check float level. The S&S carbs are fairly tolerant of debree, but built up crud or loose parts, will make a smooth runner a nightmare shortly.
Good luck. Buffalo

[92flhtcu]

I too would start on the fuel side of the issue, if all that is good, I would then venture into the ignition side. Please let us know any updates, we like to get to the bottom of problems

[joes bar and grill]

If you put the longer pipes on, that would make it run a little richer.

[Hybredhog]

      What elevation are you at? what size of jets are in it? If you started the season out with new plugs, it may have taken awhile at highway speeds to show that the intermediate jet is to large. It handles the fuel to up around 50mph, and then the main takes over.  A larger than needed intermediate jet is probably the S&S's biggest problem that people run into & is a PIA for most to figure out. Just for example where I live is 4000 ft, and proper jetting for a relatively stock Evo is a 26.5 intermediate jet, & a 66-68 main, the rest can be dialed in with the idle circuit & accel pump. Down load S&S's tuning directions for further help. As for pipes, Drop kick the Drag pipes & use muffer types, or at least put a bolt in the end of them to break up the reversion waves.

[1FSTRK]

I will be the odd man out again. The evo ignition boxes can go bad. I have seen two different indicators of boxes going out. One thing they would do is start lowering the rev limiter rpm. It would drop a couple hundred rpm at a time until someday you just could not rev high enough to go the speed limit. The second thing we saw more often was a bike that had been jetted and running fine for years would suddenly start running rich. You could rejet it and it would be fine for awhile and then it would start running rich again. I know of one guy with a 80" evo that worked his way down to 883 jets before he finally gave in and changed out the ignition box. Back then we speculated that the box was actually shortening the coil saturation time causing the spark to become weaker and weaker but really never confirmed that, we just installed new ignitions and put the original jets back in the carbs and they would dyno right back where they had been originally. If your air cleaner is clean and you have changed nothing on the bike from when it ran good to when this started to occur I would try to find a box to plug in and try.
I pass this along to you because in your OP it sounds exactly like what we went through before we figured the first one out.

[KB]

Check the coil. Borrow a known good one and see if that fixes it. Especially if it's breaking down under load.

[86fxwg]

I will be the odd man out again. The evo ignition boxes can go bad. I have seen two different indicators of boxes going out. One thing they would do is start lowering the rev limiter rpm. It would drop a couple hundred rpm at a time until someday you just could not rev high enough to go the speed limit. The second thing we saw more often was a bike that had been jetted and running fine for years would suddenly start running rich. You could rejet it and it would be fine for awhile and then it would start running rich again. I know of one guy with a 80" evo that worked his way down to 883 jets before he finally gave in and changed out the ignition box. Back then we speculated that the box was actually shortening the coil saturation time causing the spark to become weaker and weaker but really never confirmed that, we just installed new ignitions and put the original jets back in the carbs and they would dyno right back where they had been originally. If your air cleaner is clean and you have changed nothing on the bike from when it ran good to when this started to occur I would try to find a box to plug in and try.
I pass this along to you because in your OP it sounds exactly like what we went through before we figured the first one out.

Bingo...seen this more than once.
If someone changed the ignition systems to mechanical advance ignition like accell ,I've seen the weights freeze & act the same way.

86

[midwestcowboy]

Thanks to all for chiming in....gave me some food for thought.  I can rule out bad fuel, will pull bowl and check size and tightness of jets. I'm at 1550' elevation. I did an OHM test on the coil -good there.
           I have S&S set up sheet and started from scratch this past weekend... plugs were picture perfect, but still running badly. Stopped to get fuel and almost couldn't get it cranked up. I can feel popping through the pipes at idle.
           Being in the boonies makes it hard. no shops closer than 2 hours and the HD dealer doesn't fool with older bikes. I get my parts off ebay. Anyway to do a diagnostic on the ignition box ?
           One last thought. On my Panhead I had a Joe Hunt magneto, sometimes it'd go haywire, causing similar issues. I'd pull it, take it apart, put it together and reinstall, and all would be good. I knew guys who were Electrical gurus for DOD who never could figure out what was going on.... Electrical issues can be a bugger.
           I'd like more info on the pipes aspect. I have V&H long pipes with no baffle. Where, and what size bolt?
           Odd, I logged 10k since Spring, and up til a month ago she ran fine. I'll keep plugging away and will keep y-all up to date. Any further thoughts would be appreciated..Happy Trails   

[Hossamania]

Have you checked to make sure your ignition switch isn't cutting in and out?
A 1/4" bolt installed about 2" from the end of the pipe is the normal way that is done to break up reversion.

[1FSTRK]

Thanks to all for chiming in....gave me some food for thought.  I can rule out bad fuel, will pull bowl and check size and tightness of jets. I'm at 1550' elevation. I did an OHM test on the coil -good there.
           I have S&S set up sheet and started from scratch this past weekend... plugs were picture perfect, but still running badly. Stopped to get fuel and almost couldn't get it cranked up. I can feel popping through the pipes at idle.
           Being in the boonies makes it hard. no shops closer than 2 hours and the HD dealer doesn't fool with older bikes. I get my parts off ebay. Anyway to do a diagnostic on the ignition box ?
           One last thought. On my Panhead I had a Joe Hunt magneto, sometimes it'd go haywire, causing similar issues. I'd pull it, take it apart, put it together and reinstall, and all would be good. I knew guys who were Electrical gurus for DOD who never could figure out what was going on.... Electrical issues can be a bugger.
           I'd like more info on the pipes aspect. I have V&H long pipes with no baffle. Where, and what size bolt?
           Odd, I logged 10k since Spring, and up til a month ago she ran fine. I'll keep plugging away and will keep y-all up to date. Any further thoughts would be appreciated..Happy Trails

Standard ignition box diagnostics will not show a box is failing in the manor I described, that was what made it so hard to figure out.
Can you confirm that you are running stock HD nose cone parts and ignition box?
The bolt in the pipe is a nice tuning tool but usually not required in the long pipes, If you do want to try it I would not do so until you figure the original problem out and fix it. If you install the bolts and then need to re-jet you will be totally lost because of the other problem your having. If it ran all that time with those pipes and no bolt you should be able to fix what ever is wrong and it should run fine again with no bolt.

[pwmorris]

No way to tell on the Internet...many causes-
Bike was running fine with current jetting so I would focus on electrical-

Recently the ol gal has started running rough, hard to start, periodically backfiring through the exhaust, and the plugs indicated I'm running on the rich side.

Start with battery-

Check battery voltage, battery cables, grounds and voltage under load. I have had low voltage sputtering, bad grounds, bad coil, loose wires, bad regulator not bringing up voltage, bad wire at starter button and at starter, and more.

You have cleaned the carb....dig into the electrical, starting with the battery. Put a meter on it as you start it and and as you bring up revs and go from there.

No magic bullet...

[midwestcowboy]

Thanks again to all for the advice. Looks like I have my work cut out. If I have to replace electrical items ...coil, ignition, etc, are aftermarket or OEM recommended? If it's the former, whats some good bets?  Thanks

[pwmorris]

No need to pay more for OEM-I think they all come from China anyway.

When you clean carb bowl good and blow it out real clean, drain gas and unscrew and pull petcock down and out and check for gunk in screen and fuel line to carb. I have seen debris settle and be fine riding initially, then after riding a while, the crap gets stirred up and clogs the petcock screen, starving the carb at speed, and causing sputtering.
Also check tank vent and make sure it is clear to eliminate vapor lock, which also causes a sputtering condition after riding a while at speed.

Check both plug wires, and make sure they have solid connections to both plugs and coil and that both plugs are tightened good. Simple stuff that can causes issues.

Also, inspect manifold closely for cracks and spray brake cleaner where it meets heads and listen for rpm changes.

Over time, ignitions, coils, etc simply wear out and sometimes show failure with intermittent sputtering, etc, especially when they get hot.
Again, start with the elephant in the room first-battery. Take your time, go slow, and work the problem till you find it.

[1FSTRK]

Thanks again to all for the advice. Looks like I have my work cut out. If I have to replace electrical items ...coil, ignition, etc, are aftermarket or OEM recommended? If it's the former, whats some good bets?  Thanks

You should not need to do all, most of what you listed will give totally different problems when they are bad.
Is the ignition OEM now?
Are you still running a VOES?

[harpwrench]

My 90 acts the same way when the VOES ground wire breaks off. Or vacuum hose cracked.

[1FSTRK]

My 90 acts the same way when the VOES ground wire breaks off. Or vacuum hose cracked.

These are the things I have been trying to help him eliminate. The voes wire or hose  will leave the ignition on  the advanced curve, usually causing a lean style cough through the intake rather than a pop in the exhaust and should not show as "rich" on the plugs.

[pwmorris]

You eliminate possible issues by tackling them one at a time-it's the only way.
Every one of the more than dozen electrical/fuel issues can cause sputtering/popping, as I have unfortunately personally found running S&S carbs on the track and strip for over 15 years.
The fact is, that there are more than 20 causes of this issue on our bikes-and I have had to deal with each and every one of them...it sucks but if it was easy, well,......
Fuel starvation and intermittent delivery to carb (and the many causes of this issue) can cause it, as well as a host of electrical gremlins.
As said, tackle it one by one, check it off your list, and systematically eliminate possible causes.
It's the only way to find a random gremlin.....

[Tynker]

Thanks again to all for the advice. Looks like I have my work cut out. If I have to replace electrical items ...coil, ignition, etc, are aftermarket or OEM recommended? If it's the former, whats some good bets?  Thanks

Don't forget to check the intake manifold seals for leaks. It does sound like that might be the problem, hard starting, loss of low end power,ect.

[TMMWORKS]

I think number 1 is to check charging system , and then look to the top of carb ,have seen quite a few lately where caps on top of carb have broken or just plain ole missing .

[1FSTRK]

Because you state in the OP that the bike was running fine most of the season and you are confident that it is now running rich, one thing on the carb that can re-adjust itself is the float. If the bike has been hauled in a trailer/pick-up, or bounced around in some other way the float level can end up higher than where it was originally set. You may want to just re check the level to confirm it is where you set it.

[pwmorris]

Don't forget to check the intake manifold seals for leaks. It does sound like that might be the problem, hard starting, loss of low end power,ect.

Agree, and already mentioned in post 13-

the plugs indicated I'm running on the rich side

           I have S&S set up sheet and started from scratch this past weekend... plugs were picture perfect, but still running badly.

Cowboy,
Initially, plugs were rich and now you seeing them, they are fine. Did you pull them after riding the same just prior to looking at them?
You need to pull the plugs when the issue is occurring-not after idling rolling into the garage, which would give a false, loaded, possible rich reading.
Find an open road with accelerator pump off, and with a plug wrench and glove in your pocket , ride at speed trying to recreate the issue. Pull in the clutch when you hear the stumbling/popping, and shut the bike off, coasting to the side of the road.
Pull the plugs and inspect.

[Beave]

This bike doesn't have a Crane Hi-4 ignition module does it?  That's what I experienced when mine died, hard starting, popping at low speed. The S&S is a robust piece, and works best when ridden regular.  Setting will hurt it more than riding it.  I don't see it causing your problem.