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  1. #1
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    300x Endurance Build.

    In a effort to have a longer lasting stronger motor that can sustain the extreme pounding and heat of offshore and Endurance racing as well as still be rec friendly I have decided to do a complete rebuild to strengthen key areas. I will document the progress in this thread.

    Currently the crank shaft is out being lightened polished and balanced as well as having all the oil passages drilled , fluted for better oiling.
    The head is also being done at this time with a multi angle valve job on a serdi machine and stainless APE valves ti retainers and new guides and springs are being installed. The goal of this build is not to make it faster but to make it stronger so it can handle the repeated abuse for reliability. And see how long we can go between rebuilds.

    Here is a list of the major parts I am going to use in this build.

    Cp forged pistons with new bowl design,stock compression ratio.
    Crower forged rods.
    Ape head stud kit
    Ape stainless valves and ti retainers
    Polished ,lightened , balanced crank
    And some other tips and tricks for reliability.


  2. #2
    Kev273's Avatar
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    That sounds like a good build, I am looking at doing the same thing so keep with the updates

  3. #3
    My name is Sean and I am addicted to STXs smokeysevin's Avatar
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    Re: 300x Endurance Build.

    Bigger valves or standard size? Are you going to knife edge the crank? Stock cams in stock location or degree or new cams? Are you going to port the blower or just lighten it? How do you plan on tuning? Add fuel or an ecu? I have build my ecu so let me know if you want some help.

    Sean

  4. #4
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    300x Endurance Build.

    Sean I am just fortifying the stock set up so there will be no need for tuning changes. Just reinforcing and making things stronger I still want it to be a daily driver with ability to take the abuse. The ski with just a override makes more then enough power and mph. Until there is a reliable way to have a AFR gauge in the ski for hrs on end will I look at adding more fuel and a tune. This is also more of a test to see what the next week point will be if there is one. Can't do that by skewing the data to much with tunes etc. but should i want to add more to it in the future the ski will allresdy have the parts needed to take the extra power.

  5. #5
    My name is Sean and I am addicted to STXs smokeysevin's Avatar
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    Re: 300x Endurance Build.

    With a good valve job I would add 1-2 psi of fuel especially for endurance. I know I don't need to remind you but these are dumb skis and any change you make you have to compensate as the ecu can't. Rich is cooler and for endurance I would run a bit richer but that's just me. I know from my 15 that the oil pressure on these skis is pretty good, have you thought about adding piston squirters?

    Sean

  6. #6
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    300x Endurance Build.

    Quote Originally Posted by smokeysevin View Post
    With a good valve job I would add 1-2 psi of fuel especially for endurance. I know I don't need to remind you but these are dumb skis and any change you make you have to compensate as the ecu can't. Rich is cooler and for endurance I would run a bit richer but that's just me. I know from my 15 that the oil pressure on these skis is pretty good, have you thought about adding piston squirters?

    Sean
    I dont think A head with new valves and valve Job will seal that much better then stock new head and not going oversize so it should be ok I will start with stock set up and go from there.

  7. #7
    My name is Sean and I am addicted to STXs smokeysevin's Avatar
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    Re: 300x Endurance Build.

    I should have typed that differently, to run cooler and potentially prolong piston life I would add a little fuel, in my experience the kawi motor will run a little better when you add 1-3 psi of fuel, the richer mixture also burns cooler which is good for longer rides, do you need it probably not, will it help maybe.

    I'm not trying yo come across as hostile Tommy just offering another suggestion. What material are you swapping to for the valve guides?

    Sean

  8. #8
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    300x Endurance Build.

    Np Sean all suggestions are welcome.

    Bronze valve guides. All the machine work is being done By APE.

  9. #9
    My name is Sean and I am addicted to STXs smokeysevin's Avatar
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    Re: 300x Endurance Build.

    Are you going to run them straight from the box. That's cool that ape is doing it, they have some sweet tools.

    Sean

  10. #10
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    300x Endurance Build.

    I just gave it to them and let them do there magic. They know there stuff!!!!! I like the fact they make there valves springs retainers etc in house

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