Evo EFI----poping-rumble in exhaust system - Harley Forum

RKJohn · #1 03-14-2009, 08:37 AM

I need assistence with a problem on my 1998 RK Police. I have the SE 2 stage kit installed and ecm remapped with modual that came with kit.
I am trying to get the rumble/pop out of the dern thang but with no sucess.
I am aware of the race tuners etc, but dont want to go there if there is a way to tune it out or something.
If you have any knowlege that would help me figure out a fix.. by all means please repond.

Thanks
John

GrayRider · #2 03-14-2009, 10:54 AM

Sounds like it's running too lean. Assuming that it's fuel injected, I'd try a DFO in order to add some fuel. Lots of people sell them for under $200.

frisco-rigid · #3 03-14-2009, 05:10 PM

Hey RK

When did the rumble/pop start .? Has it always done it.? What changes have you made that might contribute to it..?

When does it do it.?
Under hard or easy accel or under De-call..? Normal De-cal or from waay high R's.?
At idle..?
What pipes & diameter,, & are you running muffs.?

Yes, most times Pops are a lean prob but rumbling is not..

More info please..

RKJohn · #4 03-14-2009, 06:42 PM

The rumble/poping began right after the SE 2 upgrade. It is worst when the engine has cooled down a bit say after a pip stop. Only on decel or high RPM shifting.
I am running Sampson Silver Bullet Fishtails but have tried stock mufflers which dos make it better but you still hear the rumble.
I have replaced the entire exhaust system, checked for intake leaks, raised RPM at idle with no help.

Frustrated
john

frisco-rigid · #5 03-15-2009, 04:20 AM

Yeah, I'm sure you're frustrated..

The fact that the popping disappeared with stock muffs but the rumble stayed makes me curious so I wanna know if you're running true-duals or the old-style 2-1 or 2-2.. What is their diameter & length.?

It is never easy to try to figure out a prob in such delayed conversation but my feeling is that the fault is your exhaust..
First off, fish-tails have zero flow efficiency,, just about when the exhaust is starting to lose it's velocity it's gotta squeeze outa that freakin vertical smile..
Anything that flows does so better outa round things..
And, after looking at the Silver bullets in my books they look very long..
Too long or short exhaust system and/or too big diameter ( ID ) headers will usually decrease exhaust efficiency..
I never took others word for anything, I always had to find out myself, so I ran long and short and wide headers,, with/without muffs and everyway I could modify and make muffs of my own.. I cut em bent em welded em and destroyed em and I ended up everytime with the kinda sorta generic looking headers with muffs that you see 95% of the time giving me the most power..

I will suppose that the SE 2 upgrade adjusted in a wee more fuel, hopefully..
Often popping on De-cell indicates a lean condition as Gray mentioned and often you can fatten up the low-spd jetting for a cure but with an exhaust system that is fighting you there's just no telling..
Have you run Any system AFTER the SE 2 upgrade that did Not have both probs.?

Short story---- In my 127" I had horrid popping/cracklin on all de-cell..
Of course I made sure there was NO other probs then I changed Muffs, then Muffs & headers and 3 diff carbs while jetting correctly and 3 ignitions,, ok.?
I made sure the Whole system was tighter than a bulls ass in fly season----NO leaks..
I ended up eliminating about 70% of the prob and had to admit partial defeat,, hey baby I never let a sickle prob whip my ass but this one came out a draw.. I had to accept that this motor was going to pop at least a wee bit..
I've read & heard that only rarely you find a motor that will not cease popping.. There's alota factors built in..
Alright, enough about me,, I suggest a high-spd and low-spd plug test to get a ball-park reading of your A/F mixture with the Fish-tails if you're hell-bent on using them, other-wise with other muffs that are acceptable to you..
If you're game I'm game..

RKJohn · #6 03-15-2009, 08:33 AM

Frisco, thanks for your interest in helping me out. I am running a stock exhaust header from a 2006 RK. (with plugged 02 bungs) Dia. is 1 3/4 in. I changed out the original header because it was cracked and then repaired thinking it could have a leak but it didnt help with the problem at all. The Sampsons are 31 in. long.
I am well versed in Fuel injection as I have been a Auto Tech for over 40 years and taught fuel injection at Nascar Tech. I have been keeping an eye on the spark plugs and believe the system is running lean. I am getting 43 miles per gal. Original setup got 50.5 at hwy running.
CAM CHANGES...The SE H-3 cam that came with my upgrade kit has been removed and a EV27 installed with no significant improvement, some but not much. Engine runs like a bat outa hell if you want it too. It leaves stock twin cams in the dust so that tells me that fuel is there in the higher TPS/ RPM ranges. I think ECM mapping is the problem but with talking to Harley tuners, there is no fix for that, or they dont know of one.
SO here I sit with a poping/ rumbling EVO with nowhere to go but a fuel tuner.

Any ideas men?
John

milindh · #7 03-15-2009, 02:26 PM

RJK

Having those headers with O2 bungs might work in your favor. NGK makes a real nice wide band A/F ratio analyzer system that gives you real time readings that you can see with a supplied handlebar mounted meter. There is a fairly in depth thread somewhere on this forum about it. It's called an AFX Powerdex. Google it! I believe they are under $300. It won't modify your EFI but you'll get a very good idea of what your A/F ratios are under any conditions and at any rpm. Very sweet little tuner's tool.

I don't have much personal knowledge of about Harley EFI systems but I have heard from friends and posters here that the Magnetti-Morelli systems (which I believe you have) are a real drag to work with and the end results are often not completely satisfactory. The newer Delphi systems are much better and more tunable.

Good Luck