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  1. #1
    PWCToday Guru namart1's Avatar
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    750 Rhaas pump ski carb recommendations

    Looking for carb recommendations for my 300js/750 conversion ski with 750 pump.

    Currently have a BP750 with a PJS 750 pipe (it's originally a wrap around pipe but I replaced the stinger portion that wraps the front of the motor with a stinger off one of the big Coffman 650 pipes).

    I have an SBN 44, but considering that there are lots of guys running large duals on these I'm curious as to how much I'm missing out on carb wise. SBN 46s are widely available but I think any performance increase would be negligible over the 44. Would a 48 be worth it though? And if so, where can I get a 48? I always see 48 listed as an option for SBN parts, but can't find any single 48s for sale.

    Or should I go with the dual Keihins? Although dual Mikuni 44s are tempting I have some Keihins I can run.

    Looking to set this ski up for all bottom end and am going to switch to a small pin 750 soon.

    Thanks!




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  2. #2
    PWCToday.com Is My Home Away From Home fastgtfairlane's Avatar
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    Re: 750 Rhaas pump ski carb recommendations

    if you were to do duals then definitely sbn over cdk2 but if you have the cdk2s then maybe give them a shot. i decided to try out the 3 jet dual cdk2s that came with the 750 sp that i bought. the worst part about them is getting parts. local jetski shops have sbn jets and parts but have to order everything online for the keihins. also dont like having to take the carbs off to adjust mixture screws on the keihins as i dont think anyone makes t handle screws like the sbns do. after some tuning on the cdk2s i finally got them pretty dialed in. still on the pretty rich side but it is safer on the engine. the dual carbs will drink the fuel too so if you have a stock tank expect to get about an hour out of it before needing more fuel. i have a ocjs 5.5 gal tank in mine and i can empty it in 2-2.5 hours. and the single carb will have a lot more room in the ski. also much easier to tune. since you have both why not start with one and try another?
    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

  3. #3
    Top Dog bandit88's Avatar
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    Re: 750 Rhaas pump ski carb recommendations

    My go to's are Dual SBNi 40s or SBN44s. I would never run a big single. I would even run dual SBN 38s on a 750 if I could find a manifold for them.
    Last edited by bandit88; 10-06-2017 at 04:05 PM.
    -95 750SXI
    -86 440 undergoing PJS800 conversion
    -90 TS650

  4. #4
    PWCToday Guru namart1's Avatar
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    Re: 750 Rhaas pump ski carb recommendations

    Hadn't thought about SBNi 40s. Those are the stock sxr carbs with an accelerator pump right? Still, if I try duals I'll start with the Keihins first tho.

    Fastgtfairlane you pretty much hit all the downsides to going with the duals (especially the Keihins). Aside from being a pain to tune, mainly b/c of lack of access to the adjustment screws and more expensive/less common jets I do think the carbs perform a lot better then they get credit for. are the three jet cards a lot better than the two jet? I was happy with the set of 3 jet carbs I had in the past, but these are just two jet carbs.

    The fuel consumption with duals is a significant concern in this ski. It has a kart tank... the kart tank and the ability to remove the battery without pulling carbs are pluses to a single setup.




    Any body have thoughts on a bigger single? BLRider chimed in on a PM and suggested I'd prob be happier with duals or the 44 I have, for low end. Has this been your guys' experience too?


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  5. #5
    Top Dog bandit88's Avatar
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    Re: 750 Rhaas pump ski carb recommendations

    No accelerator pump on the 40s. That is a SeaDoo thing. I only run duals and have no issues tuning them. I usually dont change my screws much either, I keep both pretty close to 1 1/4 and do the major tuning with the jets. Then a little adjust to the screws once its super close. If you are worried about fuel, stick with the single 44. Once you put on a big single, the intake signal is so low that you have to compensate bigger jets. Why are you running a kart tank?
    -95 750SXI
    -86 440 undergoing PJS800 conversion
    -90 TS650

  6. #6
    PWCToday Guru namart1's Avatar
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    Re: 750 Rhaas pump ski carb recommendations

    Thanks. Only running the kart tank because my stock tank was cracked.


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  7. #7
    PWCToday.com Is My Home Away From Home seadoobutch787's Avatar
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    Re: 750 Rhaas pump ski carb recommendations

    I scored a set of 800 sxr carbs cheap last year and installed them. I love the added performance, not the fuel economy, lol.
    1997 Seadoo SPX---limited mod
    1996 Seadoo GSX--Cruiser
    1995 Kawasaki 550/750sx---Conversion ski
    http://www.pwctoday.com/showthread.p...750+conversion
    https://www.youtube.com/watch?v=ucxd...TcG7qp45xTX9xV

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