pxctoday

» Log in

User Name:

Password:

Not a member yet?
Register Now!

» Find OEM Parts

» Jobs

» wallpapers

Results 1 to 7 of 7
  1. #1
    PWCToday Newbie
    Join Date
    Jun 2017
    Location
    CA, USA
    Age
    32
    Posts
    19

    JS550 to 550SX Pump Conversion

    After reading some old threads, I'm a bit stumped... I know about the Rhaas bearing kit and that I need the driveshaft and impeller shaft(?). What else do I need to make this conversion happen? Is it worth it? Haven't seen any concrete evidence of there being any performance difference.

    Find a 550SX hull and be done with it?

  2. #2
    Top Dog
    Join Date
    Oct 2006
    Location
    under a ton of work
    Posts
    1,845

    Re: JS550 to 550SX Pump Conversion

    not worth it.js and sx pumps are the pretty much the same and perform the same.the only advantage is the smaller shaft on sx but you can machine your js shaft down too.

  3. #3
    PWCToday.com Is My Home Away From Home BLRider's Avatar
    Join Date
    Apr 2007
    Location
    SE MI
    Age
    54
    Posts
    9,462

    Re: JS550 to 550SX Pump Conversion

    ^^^^^^^ Agreed ^^^^^^^
    Never argue with an idiot, they will drag you down to their level then beat you with experience.

  4. #4
    PWCToday.com Is My Home Away From Home fastgtfairlane's Avatar
    Join Date
    Apr 2010
    Location
    charlotte,nc
    Age
    34
    Posts
    3,240

    Re: JS550 to 550SX Pump Conversion

    the performance between both pumps will be about the same, however the sx pump is a much better design than the js550 pumps. the solid impeller shaft and factory sealed bearings of the sx pump are much better than the js pumps and the fact that the sx pump doesnt need to have grease added to keep the bearings lubed like the js550 pump does. the bearing box on the js pump takes up a lot more room in the engine compartment as well. if youre planning to stick with a 550 engine then swapping to the sx pump could be a worthwhile swap.
    91 440; PJS Viper 7000, jetsport exhaust mani, factory full pipe, coffman waterbox,solas 17*, jetco worked 440 pump, ocean pro nozzles. shredmaster ocean rideplate and grate combo, wide tray, footholds, deep strake mod, driveshaft fill,650sx quick turn

    build thread part 1: http://www.pwctoday.com/showthread.php?t=331343
    build thread part 2: http://www.pwctoday.com/showthread.php?t=364872
    build thread part 3: http://www.pwctoday.com/showthread.php?t=396154

  5. #5
    PWCToday.com Is My Home Away From Home theVetteman3's Avatar
    Join Date
    Jul 2008
    Location
    Chicago / Portage, MI
    Age
    35
    Posts
    3,840

    Re: JS550 to 550SX Pump Conversion

    It's one of those minor changes that made a much bigger overall impact prior to the Rhaas pump swap kit. On my 85 550 I went to pretty decent lengths to switch the driveline over to the SX style and I was pretty happy to do so. This required a bulkhead adaptor (Rhaas piece wasn't available back then), and a spray welded/ ground driveshaft. I had issues with the set up because the spray welding wasn't as hard as the shaft was to begin with, so it wore down a bit quicker.

    In a nut shell, in addition to the pump and bulkhead mount being a better design, the 550SX set up is also lighter, both all out weight, and rotating mass. The JS driveshaft is much heavier and the bulkhead mount bearing assembly is as well. I might have on my 550/750 build thread the weight difference between the two set ups, it was pretty substantial, maybe 3-5 lbs.

    The BIGGEST reason I did it however, was to help with alignment and reducing vibration with the 750 engine. The biggest area of inferiority on the JS design is the fact that the bulkhead bearing assembly establishes it's own centerline within itself. So you need to carefully align and shim the centerlines between the engine, driveshaft, and pump. It was all this which was proving difficult on my hull. After switching to the SX set up, you put the pump in, loosely put the bulkhead mount and driveshaft in, tighten the engine bolts down, and tighten the bulkhead mount. The bulkhead mount floats and takes the centerline established by the engine coupler and the pump spline. This is the easiest and best way how to align these parts.

    Once all that was done, the vibration levels on my 550/750 were less than my mint 2009 SJ. There did seem to be a bigger hit, like going to a lightweight flywheel. I think I have impressions on my build thread.
    1985 JS550/800 "Pretty Red": Newmiller 800, Rhaas 750 pump conv. [56.3mph gps]
    2009 1100 SJ:
    Kawi 1100
    2009 SJ MINT:
    KP steering adaptor, Worx 228 intake [45.6mph gps]
    1987 WJ650:
    6M6, JD Intake Grate, 17/20, cheater pipe [42.4mph gps]
    1994 XiR: 830cc Superstock, PJS side draft, 13/18 swirl [53.7mph gps]
    1998 SXI PRO:
    3DR hull mods [TBD]



  6. #6
    PWCToday Newbie
    Join Date
    Jun 2017
    Location
    CA, USA
    Age
    32
    Posts
    19

    Re: JS550 to 550SX Pump Conversion

    Alright, well for now I'm putting sealed bearings in my bearing box, but will be keeping an eye out for SX parts.

    I also just bought a new 5 tier shelf to put all my spare parts on...

  7. #7
    PWCToday.com Is My Home Away From Home Camasaki's Avatar
    Join Date
    Mar 2013
    Location
    Palm springs ca
    Age
    33
    Posts
    2,836

    Re: JS550 to 550SX Pump Conversion

    I bought the rhass conversion bearing for the Js.
    I planned on swapping everything this winter, but I think I'll wait until next winter when I do crank seals again.
    I can't see how it won't make a noticeable change. That js drive is so effin heavy!
    You can't drink all day, if you don't start in the morning.

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