Any last ideas before I dive into the world of custom tunes?

[yugo42]

Hello! XB12S here with a K&N and Torquehammer (originally D&D) exhaust, but no other mods. I have the dreaded XB stumble up to about 4000 RPM, most noticeable in the 2000-3500 range and at part throttle. Cruising in the city and parking lot riding are no fun at all. Full throttle operation is great, and I hear occasional misfires at idle but without any other DDFI Buells around, I don't know if that part is abnormal or if it's supposed to have a skippy idle like a Harley. I have pored over many forum threads with solutions that have worked for others that have barely changed how mine behaves.

Any other diagnostic ideas or items I am forgetting? My next move is to get Megalogviewer HD and do some ECMDroid datalogging when the weather breaks. Thanks in advance for any help!

See below for what has been tried without a noticeable change in behavior.

-new intake seals
-many TPS resets
-Buell "race" tune
-new plugs
-new wires
-breather bypass
-subframe grounding points cleaned
-new ground braid
-redundant ground from subframe to coil bracket
-D&D-specific tune from Buelltooth
-Switch from D&D to Torquehammer exhaust (heard D&D is hard to tune for)
-Back to Buell "race" tune
-static timing adjustment

All sensors appear to behave normally in ECMDroid (i.e. IAT,CLT,TPS), and AFV is always within 10% of 100. There is no obvious wiring damage. I've eliminated the fuel pump as a suspect since it performs well at full throttle, but I could be wrong in that assessment. I may have forgotten a couple of items that I checked.

 

[outthere]

TuneaBuell???????????

 

[cossack84]

yugo keep us posted in what you find. I have been trying to sort the same problem on my 04 model Buell. Was able to improve idle stumble when cracking throttle open but low load/rpm cruising is still a bit jacked.

 

[mosquito]

Search for my story How I Tuned My XB12 The Old Fashioned Way then look at the timing map. Mine was 0 degrees at idle and low rpm and throttle range which is too retarded. The bike smoothed out and started behaving when I advanced it in those areas a couple of degrees at a time.

 

[cossack84]

Search for my story How I Tuned My XB12 The Old Fashioned Way then look at the timing map. Mine was 0 degrees at idle and low rpm and throttle range which is too retarded. The bike smoothed out and started behaving when I advanced it in those areas a couple of degrees at a time.

Thats how I got the idle to smooth out.

Any way you can post your timing map?

 

[mosquito]

my timing maps

Here are my maps. I cannot remember which points i changed but I think they were all in the 800, 1000 and 1350 rpm's maybe 10 to 45 throttle pos. so you can see I didn't advance them much but it sure made it smoother. I'd be curious to see your timing maps before you change them.

 

[yugo42]

Thanks everyone, I appreciate the input! I did deep-down suspect something might be ignition-related since the different tunes changed nothing about that particular behavior. I was looking at the Tuneabuell modules too but figured I'd better start small with some narrow-band datalogging and trying to get a handle on the different software packages before I spend the $. I have ECMdroid and just downloaded the trial copy of MegalogViewer HD. I think now first and foremost I'll see where my timing maps sit.

 

[cossack84]

Here are my tables. Looks like I'm little bit more aggressive with idle advance. I'm actually thinking raising it up few degrees because it runs so much better.

 

[cossack84]

Thanks everyone, I appreciate the input! I did deep-down suspect something might be ignition-related since the different tunes changed nothing about that particular behavior. I was looking at the Tuneabuell modules too but figured I'd better start small with some narrow-band datalogging and trying to get a handle on the different software packages before I spend the $. I have ECMdroid and just downloaded the trial copy of MegalogViewer HD. I think now first and foremost I'll see where my timing maps sit.

Crappy and stumbling idle is the reason I got on this forum too lol. I like megalog viewer, great tool and its only $40 if I remember correctly.
I bought the parts from 14point7 to log wide band. Only had two runs with it monitoring both cylinders.

 

[yugo42]

Cossack84, I forgot to mention that mine is an '04 as well! Did you do a static timing adjustment before settling on those timing table values? Did you install a second bung or get a different header to monitor both cylinders?

I can't wait to get this thing sorted out. It's a blast to get on the throttle but that cruising/low-speed stumble really sucks the fun out of riding it, especially going around corners.

 

[cossack84]

Cossack84, I forgot to mention that mine is an '04 as well! Did you do a static timing adjustment before settling on those timing table values? Did you install a second bung or get a different header to monitor both cylinders?

I can't wait to get this thing sorted out. It's a blast to get on the throttle but that cruising/low-speed stumble really sucks the fun out of riding it, especially going around corners.

I did not check the static timing which I probably should. I installed a second bung in stock header. And you are right about the dang stumble, its is very annoying and some times could be a safety concern. You keep pulling a throttle and nothing happens then whole of a sudden, bam you going wide open, or at least it feels like it.
I'll try to keep up with this post as I go a long. I changed my fuel table after last ride but hadn't had a chance to go back out yet. Kinda waiting on warmer weather so its more representative of my average riding.
Let me know if you need help with anything. It sucked learning all of this on my own.

 

[cossack84]

mosquito can you also post your acceleration enrichment tables?

 

[mosquito]

fuel map

Here's the map which I use on both front and rear cylinders. Good luck, the effort will pay off! Tuning my XB transformed it from a farting, bucking annoying lump of ****e to the awesome Hot Rod it is. It idles now and pulls clean and hard from idle to red line and sounds awesome on the overrun with nary a pop...very satisfying!

 

[lowkey]

If you are going to go through the effort of wide band tuning, weld in 2 more bungs, one in the 2010 XB front header location and one that clears the RSS. Take a single wire narrow band sensor and cut off the connector and wire it up to your WB signal wire, this way you can swap the input to the ECM between the stock location NB sensor that stays installed in the header or your WB in either the front or rear second location whenever you want to datalog. I bought Vibrant Performance bungs with a curved lip to weld onto the header (you will need to reshape them to a tighter radius), I also ported out the header after the bungs were welded in with a porting long shaft rasp.

You must lock the ECM from making adjustments or datalogging will be pointless. You will also want to have a controlled route and try to keep the ambient temperatures the same for each datalog ride to get meaningful results. Flush out the portions of the datalog where were fuel enrichment is added (warmup enrichment and temp threshold). It is also imperative that you properly setup MegalogViewer to the WB you choose to use, the Voltage to AFR reading is what I'm talking about and if you don't do this MegalogViewer will be adjusting to the wrong AFR's (this is true for all software you may choose to tune with.) You can even go so far as to hang the WB O2 sensor in the air for a true lean reading and feed it in propane for true rich. I used this free software to graph out a linear line for voltage and the correlating AFR reading https://graph.soft112.com.

One last thing is all this is pointless to do if the bike isn't in absolutely perfect operating condition.




Using this guide will help anyone to understand how to tune the bike, even if you don't choose to use ECMSpy to do the tuning. http://www.ecmspy.com/ug_mono/V2.0/userguide_mono.shtml

 

[lowkey]

View attachment 11304

If you have a 12 you can use the 0 and 8000 column somewhere useful in the working RPM range, you could rescale the TPS rows and RPM columns as well.

 

[Cooter]

all this is pointless to do if the bike isn't in absolutely perfect operating condition.

X Eleventymillion :eagerness: And then double check it, and then check it again.

Hey lowkey, what do you mean about wiring in a NB sensor to the WB O2 signal wire? You aren't using a NB emulator on the existing WB? Is this a way around it? I don't want my header to look like a porcupine but thats awfully creative:up:

 

[lowkey]

Nothing as cool as that sounds. I just cut off the connector that a stock NB has and wired it to the WB harness signal wire so I can hot swap the signal wire feeding the ECM that sits close to the rear rocker box between the stock rear NB and enable the ECM to use it OR feed WB signal to the ECM for datalogging (ECM adjustment disabled). I can do this swap in a couple minutes by removing the air box outer cover and reaching in next to the rear rocker cover. On the header side I just thread in the WB to the cylinder I want to log and tune. The wiring harness I made for the whole WB setup is completely plug-n-play for any XB which is pretty cool! I'll have to get the setup out of the box and get some pictures soon as it's currently removed right now.

 

[cossack84]

View attachment 11304 Here's the map which I use on both front and rear cylinders. Good luck, the effort will pay off! Tuning my XB transformed it from a farting, bucking annoying lump of ****e to the awesome Hot Rod it is. It idles now and pulls clean and hard from idle to red line and sounds awesome on the overrun with nary a pop...very satisfying!

Thanks for the fuel map, but do you have access to acceleration enrichment tables as well?
Here is a quote from EcmSpy tinning guide: "Acceleration Enrichment is applied when the throttle is opened fast to richen the mixture and prevent the bike from hesitating whilst giving a fast ans smooth transition between steady state operating points. "

In TunerPro data in my tables looks like this and I'm thinking could be another thing that needs attention.

which is very different from the tuning guide. Thats why I was wondering if you had a table you could post up, or maybe lowkey could chime in with his.

 

[cossack84]

If you are going to go through the effort of wide band tuning, weld in 2 more bungs, one in the 2010 XB front header location and one that clears the RSS. Take a single wire narrow band sensor and cut off the connector and wire it up to your WB signal wire, this way you can swap the input to the ECM between the stock location NB sensor that stays installed in the header or your WB in either the front or rear second location whenever you want to datalog. I bought Vibrant Performance bungs with a curved lip to weld onto the header (you will need to reshape them to a tighter radius), I also ported out the header after the bungs were welded in with a porting long shaft rasp.

You must lock the ECM from making adjustments or datalogging will be pointless. You will also want to have a controlled route and try to keep the ambient temperatures the same for each datalog ride to get meaningful results. Flush out the portions of the datalog where were fuel enrichment is added (warmup enrichment and temp threshold). It is also imperative that you properly setup MegalogViewer to the WB you choose to use, the Voltage to AFR reading is what I'm talking about and if you don't do this MegalogViewer will be adjusting to the wrong AFR's (this is true for all software you may choose to tune with.) You can even go so far as to hang the WB O2 sensor in the air for a true lean reading and feed it in propane for true rich. I used this free software to graph out a linear line for voltage and the correlating AFR reading https://graph.soft112.com.

One last thing is all this is pointless to do if the bike isn't in absolutely perfect operating condition.

View attachment 11302
View attachment 11303

Using this guide will help anyone to understand how to tune the bike, even if you don't choose to use ECMSpy to do the tuning. http://www.ecmspy.com/ug_mono/V2.0/userguide_mono.shtml

lowkey I did exact same thing as you suggesting. Just keep swapping stock NB signal wire going to ecm with WB 0 to 5 v output signal. I appreciate all the suggestions and info. It took me some time to get the MegalogViewer to show proper data because of what you described. (hint to new guys be careful of some vendors giving out their suggestions/recommendations on how to set that part up, very unprofessional in my opinion).
Would you care to post your timing table along with acceleration enrichment just for a reference point?

 

[lowkey]

Crosshack84 sure, I'll have to do it in a day or two when I can boot into windows and pull the data. It takes a lot of rides to dial in the maps because of flushing out the useless data from the logs, it ended up getting to hot in AZ and I got my fuel maps 80%-90% dialed in when I stopped last season. The first thing I do is get my columns and rows set up for maximum usability in part throttle and a nice spread of RPM below 4K. NEXT I get the bike up to temp for zero enrichment then dial in the live 4 cells on each map separately to 14.7AFR. I then never let software such as megalog touch them when optimizing the fuel maps. I run an old version and choose to work on a tight RPM range and TPS input at a time to filter out data influencing a change outside this area. Using TunerProRT I set up deceleration fuel cut to like 90% from 7K to 2.5K then ramping out to idle (sorry all from memory RN) I have a D&D that doesn't pop on decel like this, also engine braking is extremely strong! There is a ton of tables and data to manipulate in TunerProRT if you don't load the "lite" version of your ECM. I was working on graphing in the WB signal data to be used in it's datalog analysis side so it would populate an adjusted fuel table but didn't finish and just used megalog as it already did the job OK. I was nervous of running without the ECM able to adjust fueling for a lean section so I started by taking AFV at 105% and adding the 5% to all of the fuel map front and rear outside of those 4 idle cells I dialed in above, I then added 2% on top of those cells just to start overly rich with the goal to only edit the maps to pull fuel OUT running analysis software. In megalog I edited the AFR table it uses to make new maps a bit as well. That is as far as I got... never messed with timing or enrichment tables. I can cruise at any RPM without issue. My thought is if I hit the desired AFR for each cell under steady state input (no enrichment) I could then back off those enrichment tables later.
I would suggest if you go back to NB closed loop enabled you take out the 3 second delay to 0 for AFV changes, I used old ECMSpy for this.


Hope this helps!