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  1. #1
    Canadian Beaver Inspector jkindt's Avatar
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    Premix with mod engine

    The instructions for the Ocean Pro head states that if you are using your stock oil injection unit, you must add 1 oz. of additional oil per gallon of gasoline directly to your fuel tank. It is claimed to need this due to the increased compression causing additional heat. Since I will need to add oil to the gasoline after putting on this head, is it better to just remove the oil injection system and go full premix?


  2. #2
    Click avatar for tech links/info, donation request K447's Avatar
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    You may or may not be keeping the head, once you have tried it.

    My suggestion is to keep the oil system for the time being, at least.

    And if you do keep the oil system long term, if you happen forget to pre-mix once in a while, no major harm will occur since the stock system is still pumping oil

  3. #3
    Canadian Beaver Inspector jkindt's Avatar
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    Not a big fan of the Ocean Pro head? What ratio of gas/oil is appropriate for this type of setup?

  4. #4
    She likes the bike. But the ski gets her wet!!!! xlint89's Avatar
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    I personally prefer premix. That way I know the oil is in there, and it's a bit more than needed. So it adds a little more lubrication to the bearings.

    I run 32:1 with no problem. I've been using an OP head at 13:1 compression for a while.

    There's some guys that think the swirls of the OP head can create hot spots leading to detonation issues.

    If it concerns you, when you have the head machined larger, you can have the swirls ground flat.

  5. #5
    Canadian Beaver Inspector jkindt's Avatar
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    32:1 is a bit richer than I had thought. But, I also don't want to burn down a fresh rebuild. I had thought that 50:1 was the magic ratio, but that is probably with a bone stock motor, not a modded motor. How would the richer mixture affect jetting? Not that my jets will be anywhere close as they are.

  6. #6
    She likes the bike. But the ski gets her wet!!!! xlint89's Avatar
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    MY BAD!!!!!!

    32:1 is for break in.


    40:1 is normal riding (might be able to go a bit leaner with synthetic oil)

    Jetting may be affected by the richer oil content, but you're far from a stock machine anymore, so rejetting is required.

    You'll need to find the correct sizes on your own.

  7. #7
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    How do you know which jets to change too? Doing short runs and seeing what the top rpms are? or piston wash? or plug chops? Checking exhaust and cylinder temps? Just trying to learn.! I'll have to tune my ski myself.Thats a scary thought/lol Newbie >>>>tuning a Pro785?
    Might have to make a trip to Chicago with the Pro in the bed. See Lugs if he's not too busy. It would be better,faster,and less headaches to drive 550 miles and get a tune up rather than me trying it.lol.
    Can ya just see me parked in front of Lugs shop yelling--(I got that first one on!, do I put the mag on or the mid on now?) lol Cars whizzing by me, Chicagions yelling, "Get out of the street -- A$$-hole"!.lol Oh look! it's Jkindt! He's here to pick up his Pro hull! Whats up dude! lol Long drive EH!?

    I'll be running pre-mix too looks like. I dont see a tank in this ski. will I have to run 40/1 or richer? The motor has 135 psi on it.

  8. #8
    She likes the bike. But the ski gets her wet!!!! xlint89's Avatar
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  9. #9
    Canadian Beaver Inspector jkindt's Avatar
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    You are lucky! At least you have a 'starting point' that will get you close. I have no idea what jets I am going to use to even get the thing to fire up at all!!! I have stock 650 jets in an engine that is anything but stock!!! It will be closer to 800cc's with compression that I HOPE to be able to run on 92/93 octane!!! I will have to find some VP C12 or something for break in until I know where my compression ends up once the rings are broken in!!!

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