pxctoday

» Log in

User Name:

Password:

Not a member yet?
Register Now!

» Find OEM Parts

» Jobs

» wallpapers

Page 4 of 5 FirstFirst ... 2345 LastLast
Results 31 to 40 of 42
  1. #31
    PWCToday.com Is My Home Away From Home cudaben's Avatar
    Join Date
    Jun 2011
    Location
    Napa
    Age
    35
    Posts
    2,583

    Re: Kinda disappointed with a heavily modified 750

    a solid 750 engine, with SBN 44 or 46, high comp head, coffman pipe, and large hub hooker will have plenty of power.

    To get more power you would need a FPP. But even a coffman pipe will rip.

    if you are having issues once this setup is achieved then I would guess there is something else going on- possibly ignition.
    "If it ain't broke, fix it till it is".

    "If all else fails, immortality can always be assured by spectacular error"
    - John Kenneth Galbraith

  2. #32
    Resident Guru bored&stroked's Avatar
    Join Date
    Dec 2006
    Location
    Mesa AZ
    Posts
    946

    Re: Kinda disappointed with a heavily modified 750

    I too was disappointed in my 750 in a 650sx. Bored 1.5mm, 175psi head, dual 40 carbs from SXR, 650 flywheel. Tried a couple different pipes. skat 9-17. Was more then a 650 but still not close to enough. A piped yami 701 would destroy it in acceleration.
    Last edited by bored&stroked; 11-04-2017 at 05:51 PM.
    '90 Superjet: ported 760, dual 44's, B pipe, ADA head 190psi, TDR waterbox, hooker 10-16, sponsons. Wife's ride
    '94 Suuuperjet: 84mm 61x, ported, protec pipe, H2o designs waterbox, Newmiller head 175psi w/girdle, protec ride plate, Protec mod'd cdi, UMI grate, RN pole -4", rev footholds, solas prop, sweet green turf+wrap.
    '95 Raider 701: Fiberglass not SMC, Hydrotrailer hitch, ugly purple and yellow everywhere.

  3. #33
    Frequent Poster vocalDyslexic's Avatar
    Join Date
    Jun 2012
    Location
    Dallas TX
    Age
    38
    Posts
    164

    Re: Kinda disappointed with a heavily modified 750

    I would place a wager on that. My issue was fixed with a hooker impeller, it was slipping the 15.5 badly and once the new exhaust is in and the 650 coffman is off, i would highly doubt a 701 with a pipe will out accelerate this setup.
    Last edited by vocalDyslexic; 11-04-2017 at 06:23 PM.

  4. #34
    PWCToday.com Is My Home Away From Home john zigler's Avatar
    Join Date
    Mar 2003
    Location
    wisconsin
    Age
    51
    Posts
    10,052

    Re: Kinda disappointed with a heavily modified 750

    We have also had issues with X-2 swaps. Engines run hard in other hulls, and lack power in the X-2.

    I recommend you drill, or change your water box to an aftermarket / free flow. 2" in and out is much better. Should also look at a larger exh hull exit, the stock one is small, and we have had problems with them being even more restricted with sealer / glue. You need a 2" for max power.
    RCJS also doing business as WATCON
    608-743-1305 9am to 5pm CST m-f
    email watcon@watcon.com

    Please visit our web sites

    new parts / products / services www.watcon.com
    used parts www.rockcountyjetski.webs.com
    thank you

    Please check out and like WATCON on Facebook

  5. #35
    Resident Guru bored&stroked's Avatar
    Join Date
    Dec 2006
    Location
    Mesa AZ
    Posts
    946

    Re: Kinda disappointed with a heavily modified 750

    Quote Originally Posted by vocalDyslexic View Post
    I would place a wager on that. My issue was fixed with a hooker impeller, it was slipping the 15.5 badly and once the new exhaust is in and the 650 coffman is off, i would highly doubt a 701 with a pipe will out accelerate this setup.
    I've run other ski's. It lost. Top speed was the same, but they'd get a good 4 hull lengths in front of me or so.
    '90 Superjet: ported 760, dual 44's, B pipe, ADA head 190psi, TDR waterbox, hooker 10-16, sponsons. Wife's ride
    '94 Suuuperjet: 84mm 61x, ported, protec pipe, H2o designs waterbox, Newmiller head 175psi w/girdle, protec ride plate, Protec mod'd cdi, UMI grate, RN pole -4", rev footholds, solas prop, sweet green turf+wrap.
    '95 Raider 701: Fiberglass not SMC, Hydrotrailer hitch, ugly purple and yellow everywhere.

  6. #36
    PWCToday Guru 01GS's Avatar
    Join Date
    Apr 2010
    Location
    WI
    Age
    41
    Posts
    355

    Kinda disappointed with a heavily modified 750

    From my understanding the stock hood doesnít flow very well even with a 650. You put a monster 750 in there you likely need more air for it to breath. There are threads about adding airflow. I did something different from what I saw because I donít have hood foam and could get pvc in there easier. You can test my theory by running without a hood and see if it pulls harder if you trust yourself not to sink it. Basically a pvc tube from the center of the hood up top into the hull. Also you can open up the stock inlet more with a dremel. I have a ported small pin with blaster limited chamber, light flywheel, stock keihn carbs, 2Ē waterbox and outlet, 170 psi and it pulls like a freight train. Top end isnít super high with the hooker 10/16 but I donít care. It probably does close to 48-50 but it gets there instantly. I have a pump stuffer too and it will jump out of the water from its own power at a standstill.


    Sent from my iPhone using Tapatalk
    Last edited by 01GS; 12-30-2017 at 07:59 PM.
    84 JS550/750 Rhaas pump kit
    88 X2 ported 750
    96 SLTX 1050

  7. #37
    Frequent Poster vocalDyslexic's Avatar
    Join Date
    Jun 2012
    Location
    Dallas TX
    Age
    38
    Posts
    164

    Re: Kinda disappointed with a heavily modified 750

    I thought about that but never came back to it. Probably should open jt up a bit before season. I stopped thinking air intake once i got it all lined out and we determined that a full throttle hit from off idle was spinning the impeller quicker than the impeller could move water, and then on top end it would get to a point and wouldnt rev and further, untill pump came unloaded out of water the accelerate hard for a sec once loaded but then same thing. My conclusion was based on fluid dynamics. Take a automatic transmission torque converter for ex. You have stall and lock up of the stator at a set rpm/pressure range. Its the point where everything becomes 'locked up' and the stator speed is matching the fluid speed and multiplication of force is no longer there. At full throttle we hit the point where the 650 15.5 skat couldnt flow any more water and it was like a engine brake, loading down the engine. Like trying to run on a sand dune. Im sure the compination of the 650 coffman, the stock airflow hood, and the drastically wrong impeller pitch all came togather to make the issue worse. Looking fwd to spring now to see how much more violent the new pipe, new dual 46's, and more airflow will be.

  8. #38
    PWCToday.com Is My Home Away From Home Bruce in SB's Avatar
    Join Date
    Mar 2005
    Location
    Santa Barbara, Ca.
    Posts
    2,841
    Blog Entries
    1

    Re: Kinda disappointed with a heavily modified 750

    On both my PJS 840 Supercylinder X2 and my 1100 X2 I had trouble with insufficent air flow. I popped out the square plugs in the hood and that was enough extra flow to make a huge difference for me. Did some permanant hood mods and all is good. Someone was selling some little air scoops to fit the square holes if you want easy...
    "Thanks" to Chris Newmiller @ Newmiller Machine

  9. #39
    PWCToday Guru 01GS's Avatar
    Join Date
    Apr 2010
    Location
    WI
    Age
    41
    Posts
    355

    Kinda disappointed with a heavily modified 750

    You are 100% correct that an impeller made for an almost stock 52 hp motor is not going to work for one with close to double the hp. The hooker works well with the power you have.

    These are the 3D printed vents mentioned above.

    [url]https://www.shapeways.com/product/EF8RVDGB6/x2-hood-vents[/

    Here are some pics of what I did. I ran it down to the battery side so if water came in it wouldnít affect the carbs. Also with it being up top facing backwards when you ride I doubt water ever gets in this way.

    Last edited by 01GS; 12-30-2017 at 09:29 PM.
    84 JS550/750 Rhaas pump kit
    88 X2 ported 750
    96 SLTX 1050

  10. #40
    Top Dog jrod928's Avatar
    Join Date
    Mar 2009
    Location
    Havasu
    Age
    27
    Posts
    1,959

    Re: Kinda disappointed with a heavily modified 750

    100% hood needs to be opened up to allow airflow, don't believe me ride your ski without the latches and try to open the hood under power.
    As for exhaust i'v run 3 different set ups and they're all fairly equal in power.
    blaster limited is my personal favorite with full 2" exhaust is mandatory!
    c4 chamber current set up good bottom end but not as strong as blaster limited
    coffman with bored headpipe 2-3 inches added to middle of chamber and 2 inch outlet at the stinger hit just as hard as the blaster limited and fit in a lot easier.
    prop 13/18 skat swirl i my prop of choice the stock x2 nozzle might be too big for what prop you got. Dont be afraid to play with nozzle size 82/85 is a good combination to start.
    as far as your jetting goes, the carb screws are only good out to 2 turns, after that the fuel is no longer metered by the jet. look at the taper of the aduster screw. There's plenty of specs on jetting for a single 46 but i don't have the because i'm a fan of dual carbs. sounds like youve got a great base to start off with. Refine the combination then make your judgement from there.
    92 X2 Ultimate watercraft MOD 5X
    96 Sport GP HX 1100
    95 HX Sport Spec 5X
    Sponsored By: JETTRIM, , The Rad Dudes, XScream, Reasonable Restorations, C57 Racing Products, Master Graphics, West side powersports, Ultimate watercraft.

Page 4 of 5 FirstFirst ... 2345 LastLast

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Powered by vBadvanced CMPS v4.2.0