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EFI Bike - Breathing Mods - rejetting?

Discussion in 'Cruisers' at netrider.net.au started by zilli, Mar 19, 2009.

  1. Hi All,

    I want to put some pipes and change the intake of my 07 VT750 C2 Shadow Spirit.

    I know with carbied bikes there are rejetting options, but for these injected bikes whats the go all?

    If i were to just change the exhaust would i need to remap the computer to allow for tuning of A/F?

    Will the stock computer compensate to a degree?

    Where can i get such a part and who can i speak to about it?

    I'm stuck guys, the US forums are not much help as their equivalent of this bike is not EFI.

  2. If it's fuel injected, you'll need a Power Commander or equivalent to change the fuelling. Around $500 + setup and tuning. Get googlin'.
  3. sweet... thanks

    i find it hard to find localised information about these bikes because the USDM model isnt fuel injected...

    does anyone here have experience with changing pipes, and if a fuel remap is absolutely required?
  4.  Top
  5. i actually saw that today, was going to post the link but i thought i'd get a broader view.

    Am i correct in assuming this still needs to be tuned by a pro?

    It's a shame that V&H doesnt do appropriate electronic gear to suit there pipes.

    I dont think ive got an answer yet on whether i absolutely positively need a tunable ecu for even just a new exhaust system?
  6. It's not absolutely necessary, the bike might just run rich, or lean. That might make it feel funny, lose power, gain power, get a strange power curve, etc etc and there's potential for engine damage if it's too far out of tune. Most probably it will be ok.
  7. i suppose thats the answer i was ofter Loz... thanks very much

    i know that when you change the exhaust on a car without tuning the ecu to suit you get certain side effects such as the ones you noted, and the ecu will compensate as best it can...

    i suppose my question was whether or not the ecu's on bikes are as clever... i wouldnt imagine some pipes/intake would throw the air fuel ratio out so much would they?
  8. The ECU will compensate some what as it is part of their normal function
    However a lot of Pipes do not have the abillity to refit the oxygen sensor which is a critical sensor for the ECU to adjust air fuel mix.
    A car has this normaly before the exhaust but after the Cat so most pepople don't have an issue with a new exhaust.
    If the oxy sensor is retained you a mostly ok with the mods but all ECUs have different ranges.
    A power comander or similar allow the bike to run on a new set of rules with or without the oxy sensor and most come with a basic set up to get you started with out to much of an issue.
    Scootworks and customdunamics have a range of efi boxes
  9. thats one thing i noticed on zpower i belive it was, they state that the o2 sensor can be negated from the pipes and it will be fine.

    As you said this sensor pics up whats happening in the exhaust gases and as such changes fuel mapping (to it's range). So i don't understand how the engine will run happily without it?

    is it possible to mod the exhaust to run the o2 sensor? or ould it be more effective to just get a new comptuer? even if you get a new one, how would you tune it if you can get a readout of exhaust gas? the old way?( spark plug colour?)
  10. you can by pass the sensor but as you have guessed you lock the ECU in to 1 only setting so it is a compromise.
    if the sensor is removed and a new PC is used then the PC usually runs its own program generally metered by road speed.
    you can put an O2 sensor in to a new pipe. It really is just a thread so no different to fitting a bolt.
    third party PCs usually need dyno time to get them right but a cruiser can get away with a ride to see if you have fuelling issues. The PCs will have a basic set up then 3 potentiometers usually idle acceleretion and high speed, Bit like a Carburetur has see how far weve come :grin: then depending on how the bike rides you should have instructions to tell you whic pot to turn and how much.
    an air filter and a exhaust would probably not warrant a new PC with the O2 still in the circuit but add a hypercharger and i would advice it.
  11. thats fantastic information mate, thank you very much.

    sorry to be a pest, but just a couple more things

    1) By air filter, i actually did mean a hypercharger or a K&N pod style filter with an adaptor. These both would flow pretty much the same level os air in, so can i presume by "air filter" you mean just a straight swap of the element into the stock box? Sounds to me like anything with more incoming flow needs proper tuning etc.

    2) Should i go down this route, are there professionals that anyone can recommend who cna do this work for me?

    Im very new to bikes as you can see, so i really appreciate the help
  12. the filters you mentioned do need a change in the ECU. the sheer volume of air that they make available is usually out of the range of the standard system
    there is no reason not to do this it is one of the better performance mods available
  13. i suppose the only reason would be cost...

    who in northern sydney could do the tuning of the new system, if i decide not to do it myself?

    although what was said above indicates that it is something that can be done using the instruction of the ECU manufacturer
  14. Sorry zilly
    I was having a seriously good time at eastern creek :grin:
    I don't know of anyone in Sydney that I can personally recomend but a chat to a few workshops would help
  15. Zilli, I have an M50 and earlier this year I put a Cobra fuel management system on (plug & play) then a set of Vance & Hines Straightshots. I took the bike to Bikecare in Adamstown,Newcastle (just a short ride up the freeway for you) they installed a K&N filter and then put the bike onto the dyno. I am very happy with the results and can highly recommend them.
  16. thank you very much gents!! much appreciated