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  1. #1

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    help with a lil tunning

    so i am running 9.5.1. pistons 1to1 pulley and the pink injectors from rd bike breaks up at around wot i was told cant run 9.5.1. properly with out a fpr so i ordered the one from R&D along with the block off, I know the stock fuel pressure is around 43-45 i just dont know what would be a safe fuel pressure to set it at, what do you guys think would give safe afr at the moment with that set up any help


  2. #2
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    You have an afr gauge on it? Gonna need one. Someone can give you an estimate on a safe psi number but every ski is different

  3. #3
    My name is Sean and I am addicted to STXs smokeysevin's Avatar
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    What ski? 250 or 260?

    Sean

  4. #4

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    No I don't have an afr at the moment have to wait a few week untill I get it and the exaust taped and died for it and its a 250, and that's what I would like to get for right now a safe psi to set it at

  5. #5
    My name is Sean and I am addicted to STXs smokeysevin's Avatar
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    Nothing is safe without a gauge, too rich and you wash down the cylinders and can burn the rings and cylinders, too lean and boom goes the engine.

    Sean

  6. #6
    Take the time to smile sirbreaksalot's Avatar
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    I ran 9.5:1 , 1-1 , and timing advance on aust 98 octane on my 07 250x ..
    Walbro pump and STOCK injectors @ 44-46psi for many hours with a safe Afr of
    11.8 -12.2 @WOT

    YOUR problem is those pink injectors are not needed. ....
    It was just another R&D guessing game tbey did back then that over fueled the engine big time.

    Pink injectors need a fuel controller if you want to run them...

    Stock injectors will work fine if you keep FP upto them...

    To prove this swap back to stock .....fp @ 45 and go for a short test...

    It will be snappier and rev clean all the way througb the rev range..

    Yes you should still Afr YOUR ski .

    But this combination has been done many times successfully ..

    250xtech.com has it all very well documented. .

    Waz

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  8. #7

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    Thanks so far but I did start using back the stock injectors but still had little breaking up at wot and ist between 44 and 46 around the stock pressure wouldn't u need more pressure for the higher compression ratio?

  9. #8
    Take the time to smile sirbreaksalot's Avatar
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    Compression doesnt affect total engine volume
    Its still the same cc ... its only an air pump to fuel ratio

    I went from 7.4 to 8.4 to 9.5 with stuff all change in fp
    But the pulley alters air volume so thats when u need to add some more fuel .

    you need to throw the stock pump & reg away

    ensure fuel pressure is stable , even at WOT , then u need a Afr gauge to ensure all is sweet .....

    I am sure when all the hardware is correct 45-46 WILL give you what you need and STOCK injectors and STOCK 07 ECU
    08 250 ECU needs 1-1.5 FP psi i found , as it is slightly leaner ECU file

    Waz

    I ran same set up for 2 years with 0 troubles
    Last edited by sirbreaksalot; 08-10-2013 at 09:18 PM.

  10. #9
    nicjak's Avatar
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    all of what waz said once i sorted my earlier issues i never had any problems with over 100hrs. but i was running 8.4s with 44-45psi.

  11. #10
    does it break up at high revs WOT or just WOT

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