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  1. #1

    Engine performance differance after rebuild.


    A while ago I droped a valve and got a factory built replacement engine.

    After the rebuild they hadnt torqued the headbolts, so I was blowing out coolant. Torqued it, and it helped but now it looks like the HG got damaged because of it and now im geting abit to much of white smoke from the exaust imo.

    And there is something else about the ski that is bothering me, I feel as if I have lost some acceleration, its not much but enough to give me doubts, and it seems like its not 100% constant either. My RPM's are set at 8350, and it get there from time to time but mostly sticks at ~8100.

    The compressor is 100% new, and seems fine.

    I added the Riva valetrain kit, can the increased force from the harder valve springs give a noticable power reduction?

    Or could it be bad timing or just me being silly? Just feels like something is off...

    I can see if this is hard to geat anything from, but any idea where I should look?

  2. #2
    Banned User
    Join Date
    Sep 2009
    Aussie Land
    stiffer springs reduce rpm slightly...

    Remedied with altered timing or more boost.

  3. #3
    mac_man_luke's Avatar
    Join Date
    Sep 2010
    South Australia
    bad head gasket wouldnt help.

  4. #4
    Would guess not

    Well, its gonna be changed together with alot of other stuff this winter I guess =)

    I have played with the idea of pulling the engine 100% apart, as I do not trust the guys that buildt it. And it would give me the opportunity to learn abit more.

    Have ordered new HG, ARP studs, Rotax racing oil jet, blockguard and Riva termo kit, also gonna service waterpump, both oilpumps and oilpreasure regulator.

    I have installed the riva valve train kit, but not the lighter valves, so Im thinking of doing that once I have the head off for the HG and the other stuff maybe.

    Not sure on how in bits and pices I want it, but if you guys have any recomandations for internal upgrades, just throw em out there, and give a good reason for it, so maybe I will do it.

    I would like to use the V-Tech 8700 RPM map some day, or even 8900 RPM, so going to try and bulletproof my engine as much as possible.

  5. #5
    ms4cd's Avatar
    Join Date
    May 2012
    SF Bay Area
    Do not touch the valves, BRP OEM -updated- units are way superior to what's out on the market. This was verified by numerous sources and I was directly informed by Erik at SpeedFreeks.

  6. #6
    shrabber's Avatar
    Join Date
    Apr 2008
    Jacksonville, FL
    Wrong timming would screw u lock the crank check the timming

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