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Bigger injector needed or no?

This is a discussion on Bigger injector needed or no? within the Grom Talk forums, part of the Honda Grom Forums category; Trying to learn more about injectors and what is right for my build. Currently running a 143cc Takegawa BBK with all associated upgrades (cam, head, ...

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Thread: Bigger injector needed or no?

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    Question Bigger injector needed or no?

    Trying to learn more about injectors and what is right for my build.

    Currently running a 143cc Takegawa BBK with all associated upgrades (cam, head, PCV, etc).

    The AFRs look great at around 12.5 throughout the gears and RPM range. Overall, the bike runs perfectly.

    I am still using the stock injector, but I'm guessing that it's operating in the top range of its duty cycle.

    I've read that changing to a bigger injector with more holes actually improves torque and combustion. I'm not sure how accurate this is, considering my AFRs are looking great.

    A lot of posts suggest using the PCX150 injector or a Yuminashi 140cc injector. Will I actually see a performance boost by switching to a bigger injector?

    Can someone chime in and educate me? Thanks.

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    If you are using the stock throttle body and stock OEM head do yourself a favor and open up the inlet tube to 26-27mm and port match that I/D to the intake port of your head and also port the intake of the head and port and polish the exhaust port and port match the exhaust port to the I/D of the exhaust pipe.

    Also do a lapping of your valve and clean and polish your valves.

    Not knowing what ECU you are using changing the F/I, I would stay with the Finbro 6 hole F/I if you can find one.

    Stay away from piggy back ECU such as the PCV-WB02, either get a stand alone ECU or flash your OEM ECU.

    Good Luck

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    I'm using a Finbro head, but stock TB.

    I don't think there is anything wrong with PCV, it's used on a ton of bikes with no problems. My build is pretty mild and it works perfectly for me. I've set AFR Target to 12.5 and it holds it well.

    I do not see the point of switching to a standalone at this point.

    I guess my question is what advantage, of any, will I get over the stock injector?

    Sent from my PH-1 using Tapatalk

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    does the PCV have the ability to log injector duty cycle?

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    Quote Originally Posted by nd4spdbh View Post
    does the PCV have the ability to log injector duty cycle?
    No idea. Need to look through the logs to see. Not sure that it does.

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    Heck, if it ain't broke, why fix it?
    Quote Originally Posted by Paultergeist View Post
    It seems like there is always one more thing to buy, THEN I’ll really notice a difference in performance.

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    Quote Originally Posted by solidjohnny View Post
    Heck, if it ain't broke, why fix it?

    This is why Jonny!

    Originally Posted by Paultergeist
    It seems like there is always one more thing to buy, THEN I’ll really notice a difference in performance.

    We all have been there done that...
    2018 Grom
    Koso 170 4V/34mm TB/Koso injector/ DIY intake/ aRacer Mini5 + AF1 + DG1
    Koso pump & chain tensioner/ Stock clutch ring / 60% stiffer springs
    Takegawa Crank Support Bearing / Takegawa Catch Can / Kitaco Clutch cover
    Clear cam sprocket cover/ Egay oil Cooler
    Ohlins F&R / Hindle exhaust w DB killer / Galfer brake line w EBC HH Pads
    Pro Taper grips, G2 throttle tube / Gromfatherz axle spacers
    Kepspeed alum. swingarm / Bar end mirror, RAM mount, USB Port
    Seat Concepts / Opmid V2


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    I don't think you need a bigger injector on the stock throttle body. I was running a 181 4v on the stock SF injector. I put on a 34mm throttle body and PCX150 injector but then the yoshimura exhaust became a bottleneck.

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