Hi everyone! I am a newbie...rode many years ago and just getting back into it...just bought a 99 ultraclassic, and learning many things here on the forums! Would like to pose a couple of questions...

The bike pops/backfires badly when downshifting or with rapid throttle closure (fuel injected)...previous owner said it has always done so, and a friend (Vrod owner) took it for a test ride and didn't think anything was wrong. But in reading some posts, I am seeing where certain mufflers create a lot of "popping" and it's got me wondering!!!....and so leads me to my next question:

Can someone please identifiy what exhaust/mufflers I have here? I assume probably stock/original but not sure.

Thanks in advance! You'all are great!!
Chucky

 

Take a better shot of the mufflers.

For the most part, popping is normal.

 

Those are not stock mufflers. The popping can be caused by a couple of things: Exhaust leak allowing fresh air into the exhaust system causing combustion of unburned fuel and/or improper tuning of the EFI system. Is there a tuner on the bike or did it ever have a custom tune? One option is to get a flash tuner and it will dial in the tune for you depending on your exhaust, intake or other mods.

 

Check your intake boots/seals on the manifold. Spray some wd-40 and if the idle changes you have a leak. If the intake seals are okay it may be running lean and you'll have to richen it up a bit to get rid of the popping on decel.

 

popping on decel does not indicate lean running.

 

popping on decal usually means air getting in there, I'd replace the muffler clamps with new, and if that doesn't cure it, new header pipe sealing rings.

 

I think poping is rich & crackling is lean.

 

First off, decel popping is not an indicator that anything is wrong. It just means that conditions are right for fuel to ignite in your exhaust.

You may have an engine that is perfectly tuned for performance or you may not have a tuned engine at all.

If the engine runs well enough for you and you don't mind the decel pop, then do nothing.

If you want a better running engine or less pop, then either get it tuned or purchase a flash tuner and do it yourself.

 

That's not what I was told by the fine folks at Dynojet and following their advice helped eliminate my issues but Im not a tuner.

 

At some point in the life of a bike certain parts should be replaced, or a least checked periodically.


For suspected exhaust leaks, new "donut" gaskets and all new muffler and pipe clamps are fairly cheap and not too much work if you have the proper tools.
A thorough inspection of the "Y" pike is also a great idea.
Mine was cracked and I had no idea of how long the condition existed.


On an EVO, replacing the intake seals is also a good idea, and again, not very expensive but it does take some time and a few tools. Well worth doing even it requires paying someone to do it for you.


If you do these things, along with new spark plugs, a new air filter. and the bike still doesn't idle/run correctly, it's time for a visit to the H-D doctor.