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Thread: Firebolt Airbox Configuration/Trouble shooting

  1. #1
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    Firebolt Airbox Configuration/Trouble shooting

    Can any experts out there help me with an airbox/stock configuration question?

    I mentioned in an earlier post that it was my intent to make sure my 2008 Firebolt was fairly close to the stock configuration as possible and within reason. (I'm not going to remove or not perform a mod if it will increase the longevity of my bike plus I like the aftermarket muffler sound) My reasons for wanting it stock are simply that I love vintage even in the mechanical configuration, possibly because, generally speaking not always, I feel like stock is the easiest on a bike, automobile, atv, etc. and its an opportunity to learn about the bike inside/out for future repairs or the addition of beneficial Mods and because it does appear to be running a little lean and will kind of cough every so often like the fuel/air might not be configured correctly.

    My bike does appear to have been modified where the previous owner removed the airbox top, cut the harness to the interactive exhaust device and cut the cable to this device as well. I am assuming the configuration of the interactive exhaust device that goes on top of the airbox only worked on the stock exhaust, am I correct?

    1. So, lets say I was starting from stock going to where I am now, what would be the minimal change that a firebolt would normally get if you just wanted to add an aftermarket muffler, Jardine, Drummer, etc.?

    2. I ordered the airbox top to replace the one missing from mine but is the airbox top going to really do anything without the "interactive exhaust" configuration installed?

    3. Does pretty much all owners of firebolts with an aftermarket exhaust do away with the factory airbox top?

    My bike is running great just has a hiccup from time to time. I had an independent and well known Harley mechanic change the oil for the first time so he would know me and be familiar with the bike in case I ever had a major issue with a motor rebuild or something like that. When I picked up, of course you get the yack yack about having a Buell but he's very straight forward and has worked on Buell's when he was with Harley up until maybe 05 ish. He said he felt like it was running lean.

    Any of you gurus out there that could help me, I want to learn and figure out all the issues above. Thanks!

  2. #2
    Senior Member 34nineteen's Avatar
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    1. If you are going to go this route, buy a Buelltooth from Rev-Mo and tell him you will be putting a Jardine on and he will probably provide you with a tune to address the flow characteristics of the Jardine.

    2. Do you have an XB9 or an XB12? If you have an XB9, there was no "interactive valve". Also, if there was and they actually did cut that, this is a red flag that the PO was a hack as the harness can be unclipped from the bike. Also, if you choose to go with the Buelltooth, you can use a program such as ECMDroid / ECMSpy whatever to disable the "interactive valve". I would also put the stock airbox top on as XB's seem to be sensitive to airflow in that area. On a XB12 the bottom of the airbox cover has a conical part that is likely used to channel air into the air horn (velocity stack). People has noticed issues when that air horn is not mounted correctly, so that cone missing COULD create an issue

    3. No.

    Most all of these bikes (or motorcycles in general) run lean from the factory for emissions reasons. The modified airbox assembly is probably allowing extra air into the motor, making it run lean. As the fuel pumps get weak, that will reduce fuel flow to the motor as well, making them run lean. As the intake seals get old and begin to leak, the bike will also run lean. The ECM will try to correct the lean condition, but it can only do so much. So, unless there have been modifications or repairs made to address these issues, it probably is running lean.
    Last edited by 34nineteen; 10-20-2020 at 04:16 PM.

  3. #3
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    Gothca thank you so much! My bike is an XB12r. I purchased a Buelltooth and the baro sensor and just received a couple of days ago. I haven't familiarized myself with it yet and I haven't got into my ECM to get the numbers to request a map and I haven't picked up an old android phone from someone (I have all apple) to use. ugh.

    Hopefully I can get the airbox top on, get an ECM tune for a Jardine Exhaust, disable the interactive exhaust (if it hasn't been already) and then be good for a while. I hate to number but its extremely helpful in learning.

    1. What do you mean by a "PO was a hack"?

    2. Just to verify, if you were modifying an XB12R from stock, say using a Buelltooth, adding an aftermarket exhaust, would you just disable the interactive exhaust, unplug and just remove the wiring harness and control cable from the bike?

    3. Also, in getting into my bike and learning about it, I watched a sparkplug changing video and noticed heat shield under the seat, in his video, over the motor/shock area. This quite possibly is minor but mine is missing this heat shield. is there any detriment to it being gone? should I replace it? I haven't noticed my butt being on fire or anything.

    4. lastly, I noticed on my cooling fan oily residue. I don't want to say its a lot because that's a relative term. its not an oil leak amount because it really isn't a whole lot of places on the motor. other than a typical blow by type about. however I am asking because the majority seems to have congregated on the fan and fan area. is this most likely the "Harley Tax"? My bike has a little over 11,000 miles on it so not really that many.

    Thank you so much for the help. Any other thoughts or advice out there are welcome!

  4. #4
    Senior Member 34nineteen's Avatar
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    Quote Originally Posted by jared View Post
    Gothca thank you so much! My bike is an XB12r. I purchased a Buelltooth and the baro sensor and just received a couple of days ago. I haven't familiarized myself with it yet and I haven't got into my ECM to get the numbers to request a map and I haven't picked up an old android phone from someone (I have all apple) to use. ugh.

    Hopefully I can get the airbox top on, get an ECM tune for a Jardine Exhaust, disable the interactive exhaust (if it hasn't been already) and then be good for a while. I hate to number but its extremely helpful in learning.

    1. What do you mean by a "PO was a hack"?

    2. Just to verify, if you were modifying an XB12R from stock, say using a Buelltooth, adding an aftermarket exhaust, would you just disable the interactive exhaust, unplug and just remove the wiring harness and control cable from the bike?

    3. Also, in getting into my bike and learning about it, I watched a sparkplug changing video and noticed heat shield under the seat, in his video, over the motor/shock area. This quite possibly is minor but mine is missing this heat shield. is there any detriment to it being gone? should I replace it? I haven't noticed my butt being on fire or anything.

    4. lastly, I noticed on my cooling fan oily residue. I don't want to say its a lot because that's a relative term. its not an oil leak amount because it really isn't a whole lot of places on the motor. other than a typical blow by type about. however I am asking because the majority seems to have congregated on the fan and fan area. is this most likely the "Harley Tax"? My bike has a little over 11,000 miles on it so not really that many.

    Thank you so much for the help. Any other thoughts or advice out there are welcome!


    If I remember correctly, running the baro sensor requires the injection to be put into open loop mode, and will not accept inputs from the O2 sensor. I'm not saying this is the wrong thing to do, but you are venturing into uncharted territory. The Buelltooth guy supports this tuning method, but most of us do not. There was another user who just posted on here about how his experiences with tuning and using this method, and is in the middle of a pickle with a weird ECM issue. I'm not knocking the Buelltooth guy, as from what I can tell he seems to be a smart guy who is trying to help... and knows more about ECM's and tuning than I do.

    1. Hack as in a butcher. Ham fisted. Should not be allowed near tools. The harness portion for the interactive valve unclips from the main harness easily. If it truly was "cut", then the one who cut is was more of a "shoot first, ask questions later" type. Proceed with caution. Also see my posting about "new XB for me" if you need more examples of "hack" for clarity.

    2. Most, if not all aftermarket exhausts do not use the interactive valve. You can disable the function with ECMDroid. If not, the bike will light up the CEL. I prefer to remove the whole assembly from the bike, but there is no harm in leaving it all in place. That control cable can be a pain to re-route.

    3. Please send a link to the video and the "time" you can see the heat shield. Doesnt ring a bell to me.

    4. This is likely a leak from the rocker box. Or did someone re-route the breather lines? I would recommend throughly cleaning the area and investigating. The oil will kill the cooling fan eventually, which can cause more problems. *I would address this first.*


    * above info taken from "Buell advanced tips and tricks - A Pennsylvanians guide to the XB platform before covered bridge decorating season begins"
    Last edited by 34nineteen; 10-20-2020 at 05:39 PM.

  5. #5
    Senior Member outthere's Avatar
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    I run a XB12r. Two different exhaust configurations and of course tunes to match. Actuator removed. Stock airbox cover, breather mod. Bike runs well.



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