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Solved Throttle cutting in and out

Discussion in 'Technical and Troubleshooting Torque' at netrider.net.au started by dbrain, Jul 27, 2016.

  1. #1 dbrain, Jul 27, 2016
    Last edited: Jul 27, 2016
    Hi all,

    I got a service last week. After it my throttle felt weird, but I kind of put it down to "they adjusted stuff and it'll just take a little bit of getting used to". Anyway, it hasn't gotten better, and I've been paying attention to it to make sure I'm not doing anything that may cause it.

    Basically something like this is happening:
    - Riding along enjoying life / cursing the heavens that are trying to drown me
    - Throttle at about mid way (bike has a throttle lock, so mid way is about 1/4 a normal throttle)
    - All of a sudden for a second or so it will feel like I've just dropped the throttle and start engine braking
    - After that it's all back to normal until it happens again

    It happens a bunch of times per trip. I've been on straights consciously holding the throttle at one position and had it cut in and out. I haven't really noticed it during heavy throttle, but I baby the bike a bit and rarely full throttle it (although I have and not seen the issue, just small sample size).

    Oh, and I've had it happen, kick back in, and then lowered the throttle to see if I'm sitting right on the biting point and I don't seem to be.

    Any ideas?


    * Oh another maybe symptom, fuel efficiency may have gone down a little. Usually my not very accurate LCD fuel reading says 340-360km of petrol remaining after filling. This time it was 310km, and my low fuel light seemed to come on earlier than it usually would (most of the time I don't see it at all). Entirely possible this is a non issue / unrelated though.

  2. Maybe the apprentice that test rode your bike after the service flogged the ring out of it, you know, absolutely rode it like the clappers, and the ecu is now expecting less than reasonable fuel economy ;-)

    In case I can actually help instead of just being a smart arse, you're the one with the triumph lams bike right?
  3. Sounds like the TPS needs replacing.
    • Agree Agree x 1
  4. Sorry, it's in sidebar but should have said in post, but yeah Street Triple 660 (LAMS).

    Haha, yeah thats why the fuel economy thing is a "maybe, but probably not related" thing. I mean even if they switched it on in the shop and left it sitting there idle for a while, that tends to mess with the fuel economy readings.
    That being said it's been a week and it's gone through 2 tanks, usually that's more than enough for the ECU/whatever to adjust the fuel guestimates.
  5. #5 dbrain, Jul 27, 2016
    Last edited: Jul 27, 2016
    I had to google it, but sounds possible that would effect it. Is this something they could have incorrectly adjusted/buggered during a service?

    * Hm, yeah that sounds a lot like whats happening. There's this "Resetting TPS" guide online as well here: Resetting The TPS Guide
    Maybe they forgot to do that as part of the service or something. Will call when they open, I have the OBD cable and what not, but would rather leave it to them. Don't know what ECU protection junk the LAMS street triples have, would rather not fry something (if thats even a possibility).
  6. It should be safe enough but best to let them do it if you have just had a service and it is not performing properly. As Dark Angel said it could be the TPS itself in which case if the sensor has a dead spot in it a reset of the TPS map will not fix the issue. Generally if the TPS is intermittent the ECU will flag an error if it notices discontinuities in the throttle position but not always.

    Short answer, you had it serviced, it is not working as it should, get them to fix it.
    • Agree Agree x 1
  7. hmmm. the rain thing has me suspicious. Maybe they didn't get a connection back together right and there is water getting into a fitting.
  8. Thanks heaps for the help guys.
    I took it in, the service guy "reset everything" (including TPS), then they test rode it and couldn't fault it (didn't ride first to fault initially). He didn't think it could be the TPS, so gave me a few options, most that would involve being bikeless for a day or two, figured I'd take it and bring it back if it's still funny.

    Working perfectly now. So I'd imagine the TPS reset did it.
    Even fixed my boggy take off, that I thought was just me getting used to the bike with all of the bits adjusted.

    Will ride again in the morning to know for sure before calling them, but every ride since the service apart from the last has been obviously quirky, so I'm marking it as solved.

    Thanks again!
    • Like Like x 3
    • Winner Winner x 1