Close to giving up and setting it on fire.

Discussion in 'Performance & Technical' started by jbone0374, Sep 2, 2022.

  1. jbone0374

    jbone0374 Rides with no training wheels

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    Sorry for the super long post, but here's the deal - I am having some technical issues with a new-to-me track/race bike that I'm having a hard time figuring out. The thing keeps shutting off on me when I am coming out of 2nd-3rd gear corners after the apex as I get it mostly upright and get back on the gas hard. This is, needless to say, a super scary situation. It just shuts down "hard" with no sputtering, warning lights, or any other indication that it's about to quit. It seems to me like its ignition related, but that is just a hunch as it never sets a diagnostic code. The first time this happened was at Road America coming out of turn 5. After having a pretty close look at the bike I decided that the tip over sensor was a pretty likely culprit. I know it isn't really advisable to bypass those (I read that some racers disable them because the lean angles that happen on the track can activate the tip over sensor), but that's what I did just to try to rule it out. Fast forward to Blackhawk and it was more of the same. I tried picking the brain of Joe at Turn One (he built the bike, more info below), but I still didn't have much to go on. He suggested it could still be tip over sensor but was having a hard time taking a guess on a solid diagnosis. I decided to throw a few parts at it based on stuff I read on the forums (I know the info can be sketchy on those).

    I had one trouble free day at Autobahn after throwing the following parts at it and decided to drag it to Putman a couple weeks ago and it quit on the 3rd or 4th lap of my second session. It always restarts, but I can't trust it to stay running on track.

    In addition to inspecting, cleaning, and applying dielectric grease to every connector I could think of, I have replaced the following
    - Tip over sensor
    - Voltage regulator
    - Fuel pump relay
    - Main fuse
    - Woodcraft ignition cylinder elimination harness (Joe @ Turn One's recommendation)
    - Battery (total shot in the dark)

    Is there anything you all think I'm missing? Short of ripping the entire wiring harness apart to inspect every related wire I'm not sure where to go with it. I'm open to all suggestions or thoughts. Could it be an actual mechanical problem? I'm thinking a particularly loose valve maybe? Something else? I know that isn't likely at all but like I said, I'm grasping at straws. Maybe something with the quick shifter or PC? Maybe the ECM? I'm sort of tired of just throwing parts/money at this, but I really don't know what to try next and I can't try to sell it with a clear conscience. After Putnam I was ready to try parting it out, but I don't really want to deal with that yet. I was ready to sell it for a huge loss providing a full disclosure of what it is and that I wouldn't trust it on the track as it is right now, but that didn't seem right either.

    I have a couple videos of this occurring but I need to edit them so you don't have to sit through the whole thing to see it. It's a bit hard to see or hear what happens, but I'll post links soon.

    The bike-2008 GSX-R 750 that has been given pretty much the full treatment by Joe at Turn One. Super bike head, bored, full suspension, quick shifter, power commander, etc.

    I would be in love with the thing if I could keep it on the track but that hasn't been the case for two seasons now. Joe has been generous with his time and has always been willing to talk to me and share his thoughts on what could be going on, so I don't want anyone to think I blame him in any way. I'm old enough to know that sometimes sh!$ just happens, but this thing has cost me a bunch of track time and cash and I could use some help.
     
  2. Dave608

    Dave608 Let's Ride!
    STT Staff

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    Check all the grounds including the main ground from the battery to the engine and also the one that is for the 5 volt reference for the sensors (it is generally on the same bolt but could have been moved). The 5 volt also has a connector in the middle of it, make sure that's good.

    Check the secondary throttle plate TPS sensor voltage, I've had one get out of spec and cause them to go haywire slamming shut and choking the engine but generally won't cause a light switch shutdown.

    Power commander also needs to be checked. Could be as simple as losing voltage which would cause an immediate shutdown so check all wires not just where they are connected but move and flex the power wires while the unit is on to make sure there are no internal breaks. I don't know how much the fueling would be off without the PC but if you could run the bike with it removed that would be the optimal way to rule it out. I've had too many issues with PC and Bazzaz myself so I prefer doing the fueling, etc with an ECU flash.

    On the ECU pull the plugs and make sure all connectors look to be fully seated just to make sure there are no intermittent connection issues, not likely but it is an easy test.
     
  3. E-Van

    E-Van What's an apex?

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    On my GSXR-1k I once had issues with the kick stand sensor. Have you checked that? I bypassed it with a wire.

    Another thought if it is lean angle related, could it be a fueling issue?
     
  4. jbone0374

    jbone0374 Rides with no training wheels

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    Thanks for the response. I've been through everything I can think of and I can't reproduce the problem with the bike in the garage. It has been a really intermittent problem. I'm thinking about just replacing the entire wiring harness because it is so intermittent. IDK.
     
  5. SirBonus

    SirBonus n00b

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    Have you checked your on/off switch?
    I had a similar issue and it turned out to be a loose wire connection with the on/off switch.
     
  6. Charles

    Charles n00b

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    If it's only happening on turns check your entire wiring harness. I'd bet a wire is exposed and shorting out when it touches the frame as you return to vert. Probably a wire near a hot spot too since a few laps would warm and soften the wire and allow it to flex/move more.

    Just my guess
     

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