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  1. #1

    787 stock oem pipe

    whats the limits of the stock pipe? like when does it give up and its time to switch to an aftermarket pipe. I have a factory pipe spec 2 but possibly deciding not to run it because id rather ride than spend the time messing with it trying to get it dialed in.
    Im building a 787 hx so just the motor alone will be almost like a piped 720. so might just run a stock 787 pipe, tdr waterbox with the exhaust rave valve on the waterbox, and a rear outlet exhaust. Will be stock stroke, .5 overbore wiseco pistons, buckshot head with pump gas domes, and mikuni 44's, with a big hub rfi pump. building a surf / rec ski so not about all out performance. i just want a lot of low end punch for playing in the surf. cylinders and cases will be ported also.

    just need to know if the factory pipe spec 2 is worth it or if the stock oem pipe will give me the hard hitting performance down low im looking for.

  2. #2
    NJ -> MD Jet ski trip fuel mileage champ carguy89's Avatar
    Join Date
    May 2011
    Lurking because I'm curious what the answer is.

  3. #3
    supposedly group k did all of their testing on a stock pipe. so their 3 levels of modifications were based on a stock pipe. they said also they got really good results with the factory pipe spec 1 but didn't mention the spec 2 at all. seems with the seadoo 787 engines they respond well to a series of modifications. that not one thing like raising compression will show gains but the combination of modifications like compression, true boring of the carbs, jetting, and some porting. I just want this thing to pull hard , and start everytime. spent all of last season working on everyone elses ski during the summer. now time for me to go play.

  4. #4
    the spec pipe on the hx will give you alot of lowend and a lil topend but you better be a great tuner to be able to get it to run on pump gas. i run the stock pipe right now in my 787 hx it runs great on 87 octane and does about 58mph on the gps and gets there quick. i pull 7080 to 7100 on my stock pipe. but since i have recently started racing my hx i am upgrading to a spec 2 but plan on paying someone to tune it for me. if you plan on running you spec 2 just be careful while tuning it.

  5. #5
    tuning the pipe as in the water injection side or tuning as in tuning the engine and the pipe with the carbs? im almost leaning more towards the oem pipe and maybe adding water injection to the oem pipe including the oem water injection from the waterbox rave solenoid. I like the fact i already have a fresh water spec 2 from a race boat but i hate that it is riddled with holes for water injection nozzles and tapped all over for egt probes. might just sell it and use the money to build my motor and just run an oem pipe. could possible run a water injection solenoid instead of the oem waterbox rave valve with a sprayer in the stock location or further up in the pipe. then drill and tap the tail cone where the exhaust coupler is so i don't melt the hose. restrict it accordingly with a carb jet. thing is i ride in the surf and don't want to constantly worry about the pipe or the water injection. so still up in the air right now.

  6. #6
    flyin' the friendly skies airbornexp's Avatar
    Join Date
    Aug 2007
    Mahomet, Il. USA
    rule number one with a spec loves to eat pistons unless you are spot on with your jetting anf carb tuning. its a race pipe that is steup to be WOT for an hour or less. its not a rec pipe.

  7. #7
    thanks, best info ive read yet. yes i know its been known to eat rear pistons, as does most coffman pipes. Think ill just sell this thing run a stock pipe and get my crank done for what i sell the spec 2 for.
    anyone want a fresh water spec 2 off a race boat. comes with ecwi controller and hardware. purchased it from wayne or the waniac sometime last year. anything that can be done to the stock pipe to increase the performance over what a stock pipe offers? id asume extrude honing the manifold would help some? Whats the thoughts of a fitting at the tail cone for a water fitting so i don't melt the coupler, and using a water injection controller and solenoid over the oem seadoo waterbox rave valve.
    seems more performance of the stock pipe could be gained with a different water injection point or turning it on and off at set rpm levels instead of based on pump and exhaust pressure.

  8. #8

    WTB Spec 2

    If pipe is still available please contact me at 602 550-2281

  9. #9
    any thoughts on the rfi pipe? supposedly the 3d rfi pipe is a dry pipe. I havent been able to fill both the carb and the rfi pipe with water and determine their volume but they should be similar. just wondering if the rfi pipe would perform any better than the carb 787 pipe.

    again any thoughts i have both and what its going in i can run either pipe.

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