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  1. #1

    engine rpm on 15f

    just bought a 15f and have done almost 4 hrs. every now and then i'll go WOT for a few seconds and notice i cant get anymore than about 7200 rpm. wot should the peak rpm be and will this increase as the engine is run in more?? thanks guys


  2. #2
    jtskir15f's Avatar
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    thats just about right. 15F's dont spin monster revs

  3. #3
    RonJon's Avatar
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    Quote Originally Posted by mootube View Post
    i cant get anymore than about 7200 rpm.
    When you say 7200, I assume you mean 7000 plus two little bars? On the rpm gauge, each bar past 7000 equals 163 rpm. If you get two bars past 7k, then you are turning between 7326 and 7488 rpm. If you were turning 7489 then three bars would show... you follow?
    Two bars is normal... Mine always turned 7k plus two bars until i added a free-flow, now I hit 3 bars easily.

  4. #4
    yep its 7k plus 2 bars. excuse my ignorance but wot does this free flow thing consist of? these engines would run well over 12k in the ninja motorbikes so i think it should be able to rev higher with some mods. any ideas, keeping budget in mind. thanks

  5. #5
    Team N2L #112 *Monster 15FKawi*'s Avatar
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    i always use to get 7100-7200 without my mods.but now im red-lineing at 7300.. she gets to speed so quick .. i got the 14/21 Solas.

    yesterday i did some testing without the bucket and rear seat. and it felt like rpm's were higher. lmao ppl on shore said they heard it whistling..and asked if it was turbo.

  6. #6

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    Quote Originally Posted by *Monster 15FKawi* View Post
    i always use to get 7100-7200 without my mods.but now im red-lineing at 7300.. she gets to speed so quick .. i got the 14/21 Solas.

    yesterday i did some testing without the bucket and rear seat. and it felt like rpm's were higher. lmao ppl on shore said they heard it whistling..and asked if it was turbo.
    Hey Monster My 07 does that with me but its only if i'm standing way back in a crouched position. Have heard folks say it sounds like a lear jet... lol
    I put a pump wedge in mine and getting 7k plus 3 bars. found it it actualy slowed down on the top end by 05 mph to 1mph. its hanging on the wall if anybody wants it.

  7. #7
    RonJon's Avatar
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    Quote Originally Posted by mootube View Post
    yep its 7k plus 2 bars. excuse my ignorance but wot does this free flow thing consist of? these engines would run well over 12k in the ninja motorbikes so i think it should be able to rev higher with some mods. any ideas, keeping budget in mind. thanks
    The 15F has two 'waterboxes.' The exhaust goes from the headers into one waterbox, and then into the second waterbox. They are aluminum and look like half-size beer kegs laying on their sides. You can bypass the second waterbox to get more acceleration and rpm. This is called a freeflow exhaust.

    As far as 12k rpm, it's not gonna happen. The 15F has a HUGE stroker crankshaft that gives it it's massive torque. It has a 15mm longer stroke than the ninja motorcycle. This slows down the rpm quite a bit. I've heard the 15F stock internals can only turn about 8500-9000 before self-destructing, but you need a turbo/supercharger to turn that much rpm.

  8. #8
    jtskir15f's Avatar
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    plus no modern pump could even be efficient spinning that many RPMs

  9. #9
    My name is Sean and I am addicted to STXs smokeysevin's Avatar
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    unless you leeched yami's gearbox thing, I think its like a reversed doubler, I dont know for sure but I know its there, my friend's fx turns 12k rpm stock

    Sean

  10. #10
    jtskir15f's Avatar
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    yes they spin like 10k but they use a reduction box to reduce prop rpms between 7k-8k

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