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  1. #1

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    Raider/GP1200 Jetworks mod

    Hey all, I've been looking into this for a while and finally got hold of the red 3/8th version (washer adjust, not twist)

    Seems there's a few different ways of plumbing this thing in for best performance so I'll ask before cutting pipes. I've got a 96' Raider 1100, engines bored to 84mm 1200, 1100 exhaust, GP1200 head. There's a great line diagram on here of a GP1200 with the flow valve fitted, basically mine is the first diagram minus the flow valve.

    3 overboard pissers. The original one from the exhaust front rubber to the hull pisser, front water outlet from the head is tee'd and goes to a second pisser and the middle cylinder has a water fitting tapped in going to the third pisser.

    Now the question. Basically which install gives best bottom end pull and top end rpm's

    -Cutting the short loop pipe on the exhaust by the temperature sensor and fitting it here (seen a few recommend this)

    -blank off the outlet for this loop pipe, tee the water pipe from the rear cylinder head and fit the flow valve to the exhaust (exactly as the diagram)

    -or leave the water pipes as they are (possibly water pressure may be to low for the valve to work well with the 3 pissers?) tap and run a second pipe from the jet pump straight to the flow valve going to the rear exhaust fitting. I can use the bilge through hull for this, I've got a Rule one fitted

    Anyone done the first version of this mod (quick and easy) then gone to the second one with dual feed and seen any improvement in rpms? The more water going into the exhaust when the flow valve opens is supposed to give you higher revs?

    great post here with the diagram
    http://www.greenhulk.net/forums/showthread.php?t=174482
    Last edited by Raider1200; 11-02-2014 at 09:17 AM.


  2. #2

    Join Date
    Apr 2014
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    Here's both diagrams. Not sure who did them originally but they're spot on. My set up's the top one without the Flow control valve.




    good pic from Cutlass of his pipe work. I'm thinking instead of teeing into the rear head pipe, run a hose straight from the jet pump feeding the valve in the same position? Jetworks themselves say you can gain up to 5hp plus higher rpm's if you increase water flow to the exhaust when the valve opens


  3. #3
    I'm trying to remember the bone stock piping. Does the hose from the inlet, where you put the jetworks fcv, just go to the fitting you eliminate when doing the mod?
    I don't have the fcv yet, i just cleaned out the exhaust, and can't remember where to pipe those two fittings to. Just Did Cutlas' carb jetting/needle/return mods. About to check pop off, and bolt her back together.

  4. #4
    I'm trying to remember the bone stock piping. Does the hose from the inlet, where you put the jetworks fcv, just go to the fitting you eliminate when doing the mod?
    I don't have the fcv yet, i just cleaned out the exhaust, and can't remember where to pipe those two fittings to. Just Did Cutlas' carb jetting/needle/return mods. About to check pop off, and bolt her back together.

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