Yea I know, this has been kicked around a bunch on this forum, but this issue is really kicking my butt. I bought an '04 Ultra a couple of months ago with what appear to be Rush slip ons. I am not sure that is what they are, but they look similar. They are 3.5". It had the decel pop so I bought a PCIII from Fuel Moto and a stage 1 air cleaner. Fuel Moto pre-programmed the tuner. After install I still had the pop. Called Fuel Moto and the had me increase the setting from 1,750 RPMs up. Started at 5 and kept going up from there. Saw minimal improvement but still had it. Fuel Moto said they had seen a few that required going to the max which they said was 50. I kept going up in increments till I got up to 50. It was still there. I started looking for exhaust leaks. Tighten the flange bolts and discovered both mufflers leaking at the joint. I have taken them off and used some muffler sealer on each joint. Put a lot on and cranked down the clamps. It is better but still there. I called Fuel Moto figuring I would take it there for a dyno tune, but they can't do it till late August. Anyone have any thoughts where I go from here?

 

Exhaust seal replacement? Another idea is to remove the heat shields around each header and look for cracks near the bends and welds. Some of the early TC88s had some issues with cracked exhaust pipes. Not all but some had issues....

 

Navyrep1 has a good point. My factory exhaust had the decel pop that would not go away. I discovered that the rear pipe was horribly cracked at the Y joint. Found a used 1 for almost nuthin'. Good luck!

 

Have you checked for intake leaks? Hard to say, plenty to search/read about the subject though.

 

Yeah, I've thrown away 2 factory exhaust systems myself. I'm saving the 3rd one just in case.

 

At what revs does the decel pop start and stop?

If you haven't already done so maybe have a look at the remaining exhaust system joints and reinstall with some new torca clamps if you find anything. Those clamps are specd as "one time use" but I reuse them and have had no issues.

Be careful about cranking down the head/flange joint fasteners-- I think the torque spec on these is pretty low, but you can tighten the torca clamps down hard.

Check around any branch joint weld where the headers join and where it splits over to the left side muffler for any cracks/leaks.
You'll see any cracks by a visual inspection as fine black (carbon) lines running (generally) along the welds at the edge of the bead in the heat affected zone of the weld.

Did the header pipe to the head joint stop leaking completely? If not you may need new exhaust header gaskets.

Always check the EZ stuff first. Let us know what you find.

 

Guys -- didn't mean to repeat things already put down-- I was typing while you had already posted.

Cheers,
V2

 

Thanks for the quick feedback. The pop seems to start about 2,750 down to about 1,500 RPMs. I will start taking off the shields and check for cracks, if nothing found I will have to replace the flange gaskets and see where that takes me. Thanks guys hope it works.

 

Good luck. If you don't take off the exhaust, it'll be pretty hard to see everywhere you need to see. Best bet is an inspection mirror and a really bright flshlight. A lot more work but the real inspection is to take it all apart. Once apart, you'll need to do new exhaust seals anyway.

If you do take it all apart, when you put it all back...loosely fit everything and make sure the headers are properly seated before clamping everything else down. Might need to reseat the headers after riding a few miles. Sometimes they "settle" a little and need to be given a final adjustment and re-torque.

Yeah, the torca clamps are supposed to be a one time use but I don't know anyone except HD that doesn't reuse them. Of course HD charges ~$25 each. I've reused many times with no ill effects.....and no leaks.

After it's all buttoned up, you can use the old cigarette smoke trick to check for leaks. If ya don't smoke, use a fireworks punk, inscence, or anything else that smokes a lot. Just hold it under any areas of possible leak while the bike is running. If it's leaking, it'll blow the smoke away from the leak.

Again, good luck. Let us know what you find. These things are always frustrating but are usually easily found with a little persistance and patience.

 

That RPM range is just about identical to my 1996 FLHT when I found the Y pipe cracked-- a normal occurance around that FLH model year.

I have read it can also mean the bike could be a bit rich in that particular zone but my money is on a leak.