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Thread: 15F engine

  1. #1
    *STX-15F* Kawi15f#12's Avatar
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    15F engine

    The 15f engine was designed off of the zx-12r engine but jus with a longer stroke rite to bring it to 1500cc?? correct me if im wrong. So what is the difference between the 2 engines? cause if they are similar or the same wouldnt we be able to use parts from them such as pistons, cams etc.


  2. #2
    jtskir15f's Avatar
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    that is a correct statement. but im not sure since the stroke is longer if that means they can inject more fuel? or if that means the valves need to stay open longer? im not sure.

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    *STX-15F* Kawi15f#12's Avatar
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    ok cause there must be a way to change some internals without having to use racing gas.

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    jtskir15f's Avatar
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    on riva's website pistons are on clearance. for fitment it says "15F superstock pistons/ 12F stock pistons" so i'm not sure if using a 12f piston in a 15f would give it higher compression?

  5. #5
    jtskir15f's Avatar
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    on riva's website pistons are on clearance. for fitment it says "15F superstock pistons/ 12F stock pistons" so i'm not sure if using a stock 12f piston in a 15f would give it higher compression?

  6. #6
    785xp's Avatar
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    I can tell you that the piston rings are the same. I found that out when I was replacing mine.

  7. #7
    hsdforever's Avatar
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    piston of 12f are not the same !! it's same motor, same bore but the stroke is more longer for the 15f.

    the piston of the 12 are bent, the head of 15f is flat !

    On this "endurance engine kit" RIVA use 12f piston, you have MORE compression with us = more power !

    be careful about level of octane gas ! you can destroy your engine...

  8. #8
    Having Fun jp1300r's Avatar
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    Stock 12F compression ratio 11.2-1, stock 15F 10.6-1.
    Last year I remember seeing some 12F's that blew up. Most likely cause detonation.
    The 15F has a .75" more stroke. This is going to raise compression too. I don't know for sure but I bet the compression ratio will be over 12:1 or more with 12F pistons in a 15F. I think you will need better than 93 octane to run.

    JP

  9. #9
    hsdforever's Avatar
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    run with 98 min ! more power on a 15 = endurance engine kit RIVA (piston 12f + CDI mitchubitchi + CAM) = 200cv !!! you destroy a Rxp with this !

    Don't forget the other part to pass power "on water" :

    - magnum pump 155m
    - intake grate
    - sponsons
    - pump shoe
    - Ride plate
    - wide nozzle
    - free flow
    - air filter

    money.... money.... money...

  10. #10
    *STX-15F* Kawi15f#12's Avatar
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    so is anyone running the endurance kit or any kind of internal mod?

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