Ok, here it goes, I got 2003 Ultra, 95" flat top s/e pistons, 203 cam. s/e a/c, #2 download. Bike runs real good but on decel burbles, pops and backfires quite angrily, tell me what you think as my tech (a local legend) seems not to put much weight into race tuners and PCII'S. I know that this subject has been beaten to death but as I am a computer refard take mercy and help a bro out. Buy the way any one interested in a place to stay for the 2010 Winter Olympics? I f you do you want to know me. Thank you all very much.

 

I thought the backfiring and decel pops were great and one of the big reasons I've liked Harleys since a young boy. Probably got an exhaust leak.

 

+1 on the exhaust leak. After installing my slipons and AC, I was having decel pops and I am the type that hates decel popping. I added more fuel to the zero throttle setting and that helped out but I still had a little decel popping. Removed and reseated the left exhaust and now I have none.

 

Maybe your Tech is a local legend in his own mind. The race tuner is the method used to "TUNE" the engine. What's he use, a wand?

In very minor decel popping conditions, an exhaust leak may be the culprit but in most cases it's the settings under the "Decel Enleanment" section of the Race Tuner program that is used to correct this condition. It has nothing to do with how lean or rich the engine is running under normal operations but rather how soon and how much the ECM orders a drop in fuel delivery when the throttle is backed off.

After I got mine straightened out using a MAP from Latus HD, I compared these settings and couldn't believe the huge difference between theirs and the factory settings.

Dump you Local Legand and find a real tuner.

 

I would say that 90% of the time your looking at a lean condition, in some cases a vacuum leak. You can pull the plugs to varify the running condition or have a qualified tech do it. It sounds like your tuner is not knowledgeable enough to work with that tuner. I'm a big fan of the Zippers Auto tune, how ever I feel that most all systems will work if you know what your doing. It's not needed, but a Dyno with a brake system would help varify the adjustment cured your problem. Let me know if I can be of any assistance, you can PM me.

 

LMFAO on legend.........man did you hit the nail on the head on that one. There sure are enough of them out there!

 

You're getting some good advice from these guys. Decel pop is caused by one or all of three things: vacuum leak at the intake, ehaust leak an the muffler, or most commonly a lousy tune. Do the easy stuff first. Spray carb cleaner or WD40 around the intake and listen for a change. Check the muffler calmps for tightness and/or remove and reseal with hi-temp rtv sealer. Find a tuner that really knows tuning and dyno tune your bike. You can go with an SERT but there are also other great options (PC V, Zippers, TTS, etc.).

 

+2 on that

 

The bike is an '03 and you don't mention if it is carbed or EFI...or how long after engine build it started this. If you've been riding on the build for a while and it just started popping than I would definately start looking for leaks first. Intake, exhaust, mufflers as mentioned. If it has done it since just after the build then it is probably the tune, but could still be leaks. PC II is for carbs, PC III or PC V is for EFI. Whatever you do choose to use for a tuning device make sure your tuner is comfortable with the system. If your tech hasn't been trained to tune, then that may explain why he isn't putting weight on their use. He may be a legend in other areas but leave the tuning to someone trained to do it. Unless it's carbed...then I see his point as it is totally unnecessary for a crabed bike as a decent tune can be achieved without a PC.