Mine is a 2007 RK Custom. I didn't buy it new but it was in great shape.

A prior owner put Python slip-on mufflers on it (which sound OK) and it also came with Screaming Eagle race tuner (SERT). So I think it's safe to assume that at some time before I got the bike, the ECM was reprogrammed.

I've had the bike for a few years and have always had a little decel popping. Last spring I found out my Y-pipe in the exhaust was cracked, so that got fixed. That was likely causing some of the excess popping. But even after replacing that, I've noticed that I get the decel popping. So I'm thinking the bike is still programmed to run lead.

Question is this: I've had the bike in to the dealer for service a couple times (spring service last year, coming out of storage and now my 30,000 service this past fall). If the bike ECM had been reprpogrammed, would the dealer have reset the programming as part of a normal servicing? I know they like to set them lean for fuel efficiency reasons. But I can't believe they would reprogram my ECM without telling me, or without doing a Dyno on it (which I know I didn't pay for). The bike isn't running badly. I'm just trying to figure out what the state of my ECM is (stock or modified). As part of this, I'm thinking about going to a Power Commander or Cobra or some sort of tuner, to help optimize the engine performance. I really, really hate the decel pop.

If I do any of the tuners (except the Cobra PowerPro), I guess I'd be reprogramming the ECM and so today's programming would be overwritten, right? But if I got the PowerPro, it would start with the baseline performance of however my ECM is programmed, and adjust from there, right?

I guess what I'm asking is what's your best guess? Do I have a modified or stock program in my ECM? And does it even matter, if I'm to get a new tuner? I don't think I'll stick with the SERT. It's a combersome beast...

Thanks

(Oh, and yes, I realize I probably don't need any sort of tuner with just the slip-ons. But I was thinking about finishing the Stage 1 with the swapping of the air cleaner, too...)

 

You don't need a different tuner. SERT is a good flash tuner. Way better than power commander or cobra. What ya need is a proper tune/map. There are lots of good stage 1 ones for the SERT out there. Do some searching.

 

You can use the SERT to eliminate the decel popping by upping the fuel a little when backing off the throttle. Do a search in the forum and you'll find some good info on it. But first learn how to use the SERT. It's not hard to use and it works fine.

 

Thanks for the help. Yeah the SERT is a little intimidating, mostly because the documentation stinks. And it's a little older, so the user interface on the computers not that great. But you're right I have found some other threads and I think I can figure it out.

My biggest problem right now is that it didn't come with cables. So I guess I can just use a normal USB to serial port cable on the one side. But I have to buy the cable to hook up to the ECU on the other side?

 

Just checking in here... did a lot of reading today. Even located the latest (and last) version of the SERT s/w - Version 4.7.7. Turns out, it has a newer map in it for my basic setup (high flow a/c, slip ons) than my original version 4.6.2 had. I think I've located cables on line, too. Just need to order. And I understand what's going on with the various tables (to a degree). My whole goal is to load the ECU with a known-correct map (I have no idea what's in there now) and then tackle the decel popping. At this point, I don't know on messing with anything else or doing a Dyno. Baby steps...

Thanks for the opinions/experience and guidance.

 

Assuming no exhaust or intake leaks decel pops are caused by a lean condition when the MAP is under 30 in a slow down. Think about taking the bike out of closed loop mode (AFR table value set to 14.6) when MAP is under 20. Try maybe going from 13.7 at 750 RPM to 12.8 at 6500 in gradual steps.

 

Thanks! This is good information. I understand the concepts of what's going on in the tuning and remapping, but I wasn't sure of the magnitude of the steps to try. I didn't know if I should back off the 14.6 to 14.5, 14.4, 14.3, etc. or if I could alter the values in greater increments. Doing it in 0.1 steps would take forever! My dealer did recommend bottoming out around 13, so that's consistent with your advice.

I know that the SERT (and my bike) also has a decel map. It seems like modifying the decel "enleanment" or enriching the AFR at low MAP values could both achieve the same results. Am I right in this thinking? Or for basic tuning, should I leave the decel map alone and just work with the AFR map?

I find it amazing that there isn't more discussion in these forums on techniques for tuning. Seems like everyone wants to either slap a Power Commander or FuelPak on their bikes, or get a dyno. Surely there are others that like to tweak their tunes on their own?

 

I assume you have the original SERT module with the bike. If yes, take it to a tuner who works with the SERT and get it remapped on a Dyno. The bike has more changes than just slip-ons if the original owner invested in a SERT, not cheap even in 2007. I would think you have a minimum of a stage 2 setup.

 

The "decel enleanment" will work to eliminate the possible pop right when you back off the throttle. But not much after that, if at all. Lowering the AFR value forces the ECM to deliver more fuel. And that eliminates the popping. But keep in mind that way too much fuel can also cause popping. So that's why you do it in steps. You need to hit that sweet spot. Try 0.3 or 0.4 at a time.


In the long run, a dyno tune is really the way to go if you want near optimal engine performance. That's because you need to measure torque and hp to do a true tune. No self tuning device has that capability and so relies on seat-of-the-pants feel. And that's simply not very reliable.

 

That makes sense. And yeah, stepping down in big values wasn't my worry. But stepping in 0.1 increments would take forever! lol

Agree 100%. My bike runs fine right now. I'm doing this more as a learning process (and a hobby). The only negative to the bike's performance is that decel pop. And it's really not bad (don't they all do it, to some degree?). I just want to tinker a little, to see if I can eliminate and learn something in the process.

Thanks!