| Author |
Message |
    
Catchbigair
| | Posted on Monday, August 06, 2007 - 01:04 am: | 
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I've bought a used '04 XB12S back in May of this year and have been enjoying riding it, but as I get more used to it I am realizing that it runs a little roughly. Specifically, it only seems to run smoothly while accelerating, and in the upper range of its RPMs. When maintaining a consistent speed it feels like it is missing every second or two. The bike has a factory race kit on it, and I'm wondering if that is the problem. I've changed the plugs recently and the ones I pulled looked pretty good, no fouling. Mileage is almost exactly what the factory says it should be, i.e. between 44 and 45 MPG highway.
This is the only Buell I've ridden (other than a friend's Blast), so I have no other Lightning experience with to compare. Do these bikes just run roughly? If not, do just the bikes with the race kits run roughly? Is it a Harley thing? |
Endoman28
| | Posted on Monday, August 06, 2007 - 08:53 pm: |
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i'm in need of some tech help on my o4 xb12r. no trouble codes will come up the engine will start surging just anytime and any rpm changed coil plugs reset tps and afm on digital tech problem goes away for a week or two then comes back. ANY HELP Please, service tech have know idea. |
Rob04xb12
| | Posted on Tuesday, August 07, 2007 - 07:50 am: |
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Ive been having the same problem with my 04 XB12S. Ive just grown to accept it, but if theres a way to fix it ill do it!
I thought it was the intake gaskets leaking a bit, so I had those replaced and it seemed to occur less, but still does it. So I did the plugs, ignition coil... all didnt seem to help! IM STUMPED! |
Blake
| | Posted on Tuesday, August 07, 2007 - 12:47 pm: |
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Bigair and Endo,
A TPS reset and check for an intake manifold seal air leak may be beneficial for your problems. To check for intake manifold seal air leak, set a warmed-up engine at a fast idle, around 2K rpm and spray electrical contact cleaner all around each seal between cylinder heads and intake manifold and also around throttle body to intake manifold seal. If/when the engine speed changes noticeably, you have identified an intake seal air leak. Be sure to prevent the contact cleaner from entering the intake as you spray. That would produce a false diagnosis.
Rob,
Have you had the TPS reset by a competent technician? |
Rob04xb12
| | Posted on Tuesday, August 07, 2007 - 07:05 pm: |
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Ive had the TPS reset, but that was before I had the intake manifold seal replaced... so maybe it still needs one?
What is it that makes a TPS reset the fix for everything??? Seems like any problem you have, just reset the TPS!? |
Blake
| | Posted on Tuesday, August 07, 2007 - 10:49 pm: |
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Problems with poor running at small throttle opening can be related to TPS. If the bike runs okay otherwise, the TPS recalibration for the ECM is indicated, among other things. It is not unheard of that some technicians do not perform the TPS reset procedure properly.
Any time the throttle position sensor itself has been touched, like during an intake manifold seal replacement, it would be prudent to perform the ECM recalibration, meaning the TPS reset procedure. |
Heyfred
| | Posted on Monday, August 13, 2007 - 11:36 pm: |
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I have a 04 XB12R at which I have had issues with, such as you are having.
My suggestions are as follows in correcting your issues are as follows:
* Replace intake seals and put a light coating of wheel bearing grease on them so they will slide on the intake manifold as the cylinders grow from heat while running.
* Leave the K/N and race muffler on.
* Replace the Race ECM with Stock one.
* Redirect the rocker box vent tubes so the hot air is not close to the IAT sensor.
* Clean the IAT with a Qtip and alcohol to get the oily film of it from the vent tubes
* Set your idle at 1000 to 1050 rpms while looking at your tach on the bike.
* At this time leave you timing at the stock setting.
Once you have done the above,tell us the results. Then I will take you to the next step if needed.
My bike has no stumbling at the 1000 to 1400 rpm range while rolling on the throttle and pulls like a bandit to redline. |
Catchbigair
| | Posted on Tuesday, August 14, 2007 - 02:53 am: |
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Thanks for the feedback Heyfred. I don't know my bike that well so need to figure out what rocker box vent tubes and IAT sensor are, though the latter sounds like an air flow meter. Looks like we are in the same general neighborhood - I'm in Bellevue. Want to go for a ride some time? |
Sparky
| | Posted on Tuesday, August 14, 2007 - 11:28 am: |
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The Intake Air Sensor (IAT) is a delicate looking smallish blob on two wires sticking out of the floor inside the airbox.
Heyfred, do you have any details on what you did wrt the vent tubes? |
Rob04xb12
| | Posted on Thursday, August 16, 2007 - 02:42 pm: |
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HeyFred,
I have the Open airbox conversion on my 12S, so there are no breather tubes in my airbox. I cleaned the IAT sensor with some alcohol and a Q-tip, and I even changed the plugs. I had the seals done about a month ago. I have the stock ECM on the bike. My idle is set at around 900 RPM, how would I turn that up?
All your tips didnt seem to fix the problem, what is the next step?? |
Al_lighton
| | Posted on Friday, August 17, 2007 - 10:14 am: |
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The "rough running" that I've heard described here seems to be pretty normal for many Buells.
When running in closed loop mode, the system is always running at 14.7:1 on average, but never AT 14.7:1. It maintains the average of 14.7:1 by alternating slightly rich, slightly lean, slightly rich, slightly lean, etc.
I believe that the steady state "roughness" that you are referring to is when the engine is commanded on the lean side, but overshoots a little and has a lean miss, or perhaps more correctly, some lean weak combustion cycles.
If you want to do a test to see if it is related to this, disconnect your O2 sensor and see if your issue goes away. If it does, then your problem is clearly related to closed loop operation.
Is there a fix? I don't know. Some bikes seem to do it more than others, so clearly something can make it better. But I don't have a good idea what it is. Some bone stock bikes do it more than modified bikes, some modified bikes do it more than bone stock bikes. I've never been able to pinpoint precisely why some run "rougher" than others in closed loop.
Al |
Heyfred
| | Posted on Friday, August 17, 2007 - 06:57 pm: |
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I have been riding my bike all week in traffic,freeway and different times of the day to vary temp changes. Fiding the sweet spot for TPS and timing.
Driving in stop and go,High 70s, low 80s, no pinging, hesitation or fan coming on. The timing has been bumped up also.
The engine has a bump bump tone rather than a Bap Bap sound when idling. It is as if the engine is not laboring to idle.
The engine pulls good from low rpm to redline.
(Message edited by Heyfred on August 17, 2007) |
Rob04xb12
| | Posted on Friday, August 24, 2007 - 07:25 pm: |
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Heyfred,
How much did you advance the timing? |
Heyfred
| | Posted on Saturday, August 25, 2007 - 02:47 pm: |
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I have been doing alot of testing and the engine keeps preforming better. Went thru 7 tanks of fuel in 3 days. On friday, I was riding all day and stayed up till 1:30 AM saturday morning testing.
Welded the hole back up in the throttle body blade and used the plugged of vacum port in the throttle body instead. Ran a vacum line from the port to the air box, to the inside of the air filter so the air is being filtered as it draws.
The engine is idling even smoother, pulls harder on the top end and is very rider friendly is various climate temps and traffic conditions.
Took the bike down to my local Buell dealer and let the Buell tech ride the bike at 2 different times. Each time I did changes that I felt were improvements. Needed a second opinion. The response was positive both times.
I have one more test to try.
The engine pulls smooth and hard from idle to redline and no detination.
I do not have any hard numbers for timing.
Had to take some timing out for the last modification because I had detination at low rpms.
Been riding saturday morning in cooler weather and not having any issues with my current set-up.
I am seeing light at the end of the tunnel. |
Heyfred
| | Posted on Sunday, August 26, 2007 - 01:16 am: |
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Rode till 6:00pm. Cooler weather, warmer weather and rain today. Went riding in freeway, city and heavy stop-n-go traffic.
Engine stayed cool, fan never kicked on. Only time fan came on was when I turned off the engine, then it cooled the engine in a short period of time and shut off.
Adjusted TPS and timing while test riding for rideability and seat of the pants performance. I need get a timing light so I can see where the timing is set at.
Bike starts easily hot or cold.
Engine idles at 1100 rpms.
No stumbles or hesitations from idle to redline. The engine pulls smooth and hard to redline, weather roll-on or just grabbing a hand full.
Updates:
 |
Sparky
| | Posted on Monday, August 27, 2007 - 01:32 am: |
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Heyfred, just to clarify, when you said you adjusted the TPS in your 8/26 post, you meant the idle speed, right? And not a TPS reset where the zero setting gets sent to the ECM?
What you are doing sounds interesting, but what is the theory behind closing the air bleed hole in the throttle plate and using the EVAP vacuum port with a hose to the air filter? Isn't that adding extra complexity and weight? Yours must not be a California model. |
Heyfred
| | Posted on Monday, August 27, 2007 - 02:46 am: |
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Yours must not be a California model.
correct
But what is the theory behind closing the air bleed hole in the throttle plate
I drilled the hole in the throttle plate to see if the hesitation off idle to about 1400 rpms would go away and it did. My theory is that the air velocity behind the throttle blade as it opened was to slow on slow accelleration was causing the issue.
Then I decided to try the plugged off port and had good results.
Heyfred, just to clarify, when you said you adjusted the TPS in your 8/26 post, you meant the idle speed, right? And not a TPS reset where the zero setting gets sent to the ECM?
No,I did adjust my TPS only, not touching the idle. I removed my TPS and slotted the holes and loosened the 2 bolts holding it on, set it manually using a volt meter once idle was set. By doing this, only one thing is changing, not rpm and TPS
Went riding today, adjusted the timing and found the sweet spot. The engine pulls smooth and strong from idle to redline.
Front wheel carries in second. If I bump the timing up, the bike becomes real aggressive.
(Message edited by Heyfred on August 27, 2007) |
Heyfred
| | Posted on Monday, September 03, 2007 - 02:52 am: |
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Went riding on the back roads today, approx 50mi. This where I really noticed the difference in engine performance. Up hill acceleration in second and third is impressive.
No over heating or detination issues. The fan comes on when the engine is turned off and only runs for a short period of time.
Hot and cold starting, no issues. |
Heyfred
| | Posted on Monday, September 03, 2007 - 05:50 pm: |
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I am done. Went on a 160 mile road trip on the freeway. The engine runs smooth and effortlessly while cruising at 3800rpm.
In conclusion, here is what I did:
* Plumbed vacum port into airbox
* Set idle to 1100 rpm.
* Slotted TPS holes so it can be rotated clockwise manually to desired voltage.
* Moved rocker box vent tubes away from IAT.
* Advanced timing till pinging started, then backed off.
Next, I will be working on improving the headlights so I can ride at night. |
T9r
| | Posted on Tuesday, September 11, 2007 - 09:43 am: |
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Heyfred,
Do you have any photos of the slotted TPS?
This is great information you've provided. |
Treadmarks
| | Posted on Friday, September 14, 2007 - 10:41 am: |
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Good Info Fred.
I would like to know how far you advanced the timing as well. |
Heyfred
| | Posted on Sunday, September 16, 2007 - 08:17 pm: |
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Reinstalled the race ECM, road the bike in traffic and on the freeway. The engine had no issues with pinging or over heating.
No starting issues hot or cold.
The engine pulls harder from idle to reline.
Not stumbles or hesitations. |
Treadmarks
| | Posted on Wednesday, September 19, 2007 - 07:57 am: |
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Heyfred,
Your tps closed setting of .946 vdc, Is that at the idle position or is that with the throttle plate closed all the way? |
Heyfred
| | Posted on Wednesday, September 19, 2007 - 09:25 pm: |
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Idle position.
First set the idle.
Then set TPS from that baseline. |
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'04 XB12S runnning roughly