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  1. #1
    dsw222's Avatar
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    Clarification on jetworks holeshot mod please?

    I'm having a hard time grasping how this is installed. I read the sticky how-to and looked at pretty much every post that comes up in a "jetworks" search.

    I understand that the concept is - Water is injected into the stinger to cool down the exhaust system and work as part of the "tuned exhaust". That water collects in the waterbox at idle and has to be blown out during heavy acceleration so the ski doesnt bog from having to blow it out before getting good power. So thats where the jetworks valve comes in. It doesnt allow water in under 2800-3500 RPM (depending on where you read about it), so the water box dries out at idle and you get the full power at launch

    I'm not getting the hosing system. I am currently looking through the shop manual and it doesnt have enough detail for me to pick up what i'm not understanding

    I understand that instead of the stock water induction into the exhaust, you tap into the pump and run a hose through the transom, which will provide the water for this mod (but where does the stock system's water come from?). It looks like that new water-in line will connect to the jetworks valve, and then go into the stinger. It also looks like the stock water-in line can be directed out the deck with a through hull pisser.

    I don't understand where the other hoses come in and why they are needed....

    Can someone please help me understand this? This is my first ski, and I've been catching onto the other mods so far... just not this one. If you know of another post that might help me (that didnt come up in my search) i would really appreciate you pointing me to it

    Thanks a lot!


  2. #2
    Moderator beerdart's Avatar
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    The stock water comes from the exhaust. When you install the jet-works mod you block the stock water by installing a solid gasket. There are two methods to get water to the valve 1. From the pump as a separate line. 2. use the stock water that is blocked by the solid gasket.




  3. #3
    "just sayin".. jetdave56's Avatar
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    If I may add...in your Q "where does your stock system water come from"...it all originates from the pump strainer as pic shows....it has a water passage leading thru the pump into its own hose up to the manifold then the engine.. .both the cooling water to the engine and a additional separate hose to the jetworks blue valve,which runs thru the transon which is drilled opened, is caused by a vaccum of water pressure moving it threw all its passages...Click image for larger version. 

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  4. #4

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    Taping the Lower and upper nipples

    After reading through alot of thread about jetwork I wasn't able to find detailed info regarding the Tap on the nipples. I pretty much understand the whole concept of the jetwork mod just not sure about the Tap. My question is when drilling and taping the nipples is it suppose to go through to the bolt hole that connect the flange to the stinger? (pix 1) If so how far down do i drill?

    And is the hole suppose to be partially in the Gap between the jacket and outer casing? (pix 2)
    BTW not my pix

  5. #5
    if you are relocating the water temp sensor, then yes, the hole goes thru into the water jacket, but do not drill into the exhaust tube/passage...

    you`ll need to shorten that bolt, or add washers so the threads do not obstruct the water to the sensor. Use 1211 sealant or equivalent on the bolt threads...
    also, toss that rubber gasket (if you bought an IR holeshot kit) in the trash and use a solid metal block off plate (homemade) or purchase from Gus with 2 OEM gaskets...

    there are several ways to dump the water from the pipe, some use the top fitting method and some use the bottom fitting to allow most of the water to drain... read up, its somewhere on this site...

    here is one thread about it:> http://www.greenhulk.net/forums/show...t=jetworks+mod

  6. #6

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    Wow. A picture is worth a thousand word. Thanks
    For the bottom nipple is it also drilled similar to the upper nipple? Straight down the nipple thru the existing bolt hole and partially into the water jacket?

  7. #7
    according to Jeff`s pics in that thread, it does look like the bottom standoff is used for the exit/dump line.
    just a note, there is no performance difference if you choose either way, the bottom hole just lets more of the water out of the pipe. I had run the top fitting with no worries, and maybe just a few ounces of water remain in the pipe...
    Shoot WFO or Jetdave a PM, they can better specify what to do...

    also if you do a yamaha forum search you`ll find this mod done in several build threads with pics...

  8. #8

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    I just got my Jetwork mod installed. I will be taking it out this weekend to adjust the opening point. Unfortunately I don't have a tach installed yet. Can anyone tell me in MPH roughly what is equivalent to 3000 RPM? Ill be sure to fine tune once tach is installed

  9. #9
    Quote Originally Posted by thatmrb View Post
    I just got my Jetwork mod installed. I will be taking it out this weekend to adjust the opening point. Unfortunately I don't have a tach installed yet. Can anyone tell me in MPH roughly what is equivalent to 3000 RPM? Ill be sure to fine tune once tach is installed
    worst case scenario, use the factory tach as a guide. there really is no exact mph for 3K bc the ski is barely moving and pushing water and not on plain and you could go from idle to 3k in a sec considering the ski idles 1350+
    so basically a soon as you pull the throttle you could be right there and hardly moving until the ski gets caught up with the speed of the prop, ya know what I mean...
    I had no problems with setting mine to 2700 rpms. with tiny tach of course and running this way. some like it a bit higher 3-3.5K...

  10. #10

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    Should I go off 3 bars? hopefully that is somewhat equivalent to 3000 RPM

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