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  1. #1

    '96 SL900 to 1200 conversion questions

    Hi all, my first post ever...!!

    I just bought a '96 SL900 that has been converted to a 1200 for a pretty decent deal. The cylinders (from what I understand) are from a MSX 140 carb, and it has a union bay billet head with 92oct domes, and VForce 3 reeds. The CDI has been reflashed to the 1200 ignition map, and the jetting has been somewhat roughed-in, but I think its a little fat. It also has the upgraded ignition kit for the 1050.

    All of the other components are from the stock SL900. The components I am the most concerned about are the carbs (I know the 1200s are larger), the exhaust manifold, the pipe, and the waterbox. Are the exhaust components restricting the 1200, or were they common between 900, 1050 and 1200? Also on the carbs, will there be a big advantage running the larger 1200 carbs, and if so, where can I find a used set for a decent deal? I am not interested in aftermarket carbs. If I keep the stock carbs, what is a good jetting setup? I am at about 1000ft and only ride above 60 degrees.

    Is there anything else that I am missing that should be changed when going up to the 1200? I am not sure if the impeller is from the 900 or a different one...is there a way to tell?

    One other thing, I rode the ski a bit this past summer prior to buying it, and it had a weird starting issue. Cold, it seemed to start fine, but after killing it hot, it would not start again after a ton of cranking. Then suddenly, it would start. I did research on the CDI power wire service bulletin, and noticed that this had not been done to this ski...maybe that will fix the issue?

    Anyway...any help you could provide would be very helpful. Thanks!


  2. #2
    SPEED KILLS, BUT YOU GET THERE QUICKER Keddano's Avatar
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    Welcome to the HUlk. Sounds you have a interesting ski there.

    First the msx 140 was fuel injected,no carbs. You could have the 140 cylinders with you saying you have a Union Bay head on it,As the 140 cyls and the 1200 triples are different. The exhaust manifolds are the same between the 900,1050 and 1200 as far as I know.

    The exhaust pipes and water box are all the same. What exhaust pipe is on it? The Black Log pipe or the Red pipe? Since the Carbs didn't come on a 140 the jetting may and would be different.

    Also what type of carbs are on it? Mukuni's or Keniths? As far as proping,that would be determined by what RPM's your able to turn and how the holeshot is. If you can find a # on it we can determine which one it is.

    There isn't any differentce in CDI's between the 1050 and 1200, but they can be recurved.Randy at Watcon is the only person we knows that does it.

    Sounds like someone had a good idea of performance mods.

    Please post some pictures,they tell alot,and we love Ski Porn!

  3. #3
    Perhaps the cylinders are from an early Genesis carb? Not sure. I will snap some photos tomorrow and post. The exhaust is a red log, and the waterbox is red also.

    This ski is a blast to ride, I am just trying to figure out how big a deal the smaller 900 carbs are, and how much I am leaving on the table performance-wise.

    Thanks!

  4. #4
    SPEED KILLS, BUT YOU GET THERE QUICKER Keddano's Avatar
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    One of the guys that know the stock domestic motors can fill you in on the carbs, I thought they were all 40mm carbs on the domestic triples. The Union Bay head makes me think you might have the 140 jugs,What type of intakes are on it? One piece or 3 seperate ones?

    The Red Pipe is the better pipe.

    Can you find #'s on the jugs? Pictures, LOL

  5. #5
    Click avatar for tech links/info, donation request K447's Avatar
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    Quote Originally Posted by bigred70 View Post
    ...I just bought a '96 SL900 that has been converted to a 1200 for a pretty decent deal.

    The cylinders (from what I understand) are from a MSX 140 carb, and it has a union bay billet head with 92oct domes, and VForce 3 reeds.

    The CDI has been reflashed to the 1200 ignition map, and the jetting has been somewhat roughed-in, but I think its a little fat. It also has the upgraded ignition kit for the 1050.

    All of the other components are from the stock SL900.

    ...I am not sure if the impeller is from the 900 or a different one...is there a way to tell?

    ...a weird starting issue. Cold, it seemed to start fine, but after killing it hot, it would not start again after a ton of cranking. Then suddenly, it would start.

    I did research on the CDI power wire service bulletin, and noticed that this had not been done to this ski...maybe that will fix the issue?...
    Welcome to the Hulk

    Updating the CDI power connection should fix the hot re-start issue.

    Make sure the Orange wire(s) have full power when the engine is cranking and running. The bilge pump is supposed to run continuously when the engine is running, and is powered by the Orange wire. With the CDI wiring change, the CDI is also powered by the Orange wire.

    Take some clear photos of the engine, both intake/carbs and exhaust side.

    Do you know if the cylinders are stock MSX 140, or have been ported?

    I would expect the impeller to be changed, since the 1200 motor puts out more power, and would run over the RPM limiter with the stock 900 impeller.

    If you remove the jet pump (which is a good thing to do anyway), you can see the part number embossed on the hub of the impeller. While you have the jet pump off, check the pump bearings for any signs of noise or roughness when turned by hand.

    When you rode it, did you note what the maximum RPM was during full throttle runs?

    Click below for more info

  6. #6
    Watcon's Avatar
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    900

    The 900 shouldnt need the updated wiring for starting.. (unless somebody changed it). Most likely the jetting is too rich on the low speed circuit or the the float valves are leaking when the fuel tank is pressurized.

    The 900 carbs are 38 mm, and the 1200 carbs will help..

    The OEM 900 impeller is an excellent chouce for rough water, and hooks up well, but you will make more Mph with an OEM MSX-140 impeller (or others)... Take 447's advice, and Rpm your ski first.. Then jet your jetting dialed in before changing form the OEM impeller.. I think the OEM is a #554, but somebody from the group can verify this from the application charts.

    Have fun!
    Randy

  7. #7
    Click avatar for tech links/info, donation request K447's Avatar
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    Quote Originally Posted by Watcon View Post
    The 900 shouldn't need the updated wiring for starting.. (unless somebody changed it).

    ...The OEM 900 impeller is an excellent choice for rough water, and hooks up well, but you will make more Mph with an OEM MSX-140 impeller (or others)...

    Take 447's advice, and Rpm your ski first.. Then jet your jetting dialed in before changing form the OEM impeller.. I think the OEM is a #554, but somebody from the group can verify this from the application charts...
    The CDI has been updated (1050 Update Kit?), so I would think it would want the CDI power wiring update
    Shouldn't hurt, in any case.

    bigred70 - What is the part number on the actual CDI?
    Is there a hand marked number on the back of the CDI?

    Stock impeller for the 1996 SL900 was 5131337, spec'ed as 17-22 pitch.

    For the '1200' engines in 2 seater hulls, the 2000 SLX had the 5132202 Nu Jet 7.0 Mod, slim (.550)
    The larger 3 seat 2000 Virage TX used the same impeller.

    For 2001 onwards, the Virage TX used the 5131554, spec'ed as 17-25 Swirl.
    The same '554' impeller was used on the 1998 SLTX (3 seater) and SLXH (2 seater)
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

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  8. #8
    Moderator beerdart's Avatar
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    Welcome to the hulk

  9. #9
    Watcon's Avatar
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    Impellers

    The #337 is a good impeller, start there if thats what he has already.. I also liked the #554 for closed course racing.

  10. #10
    PolarisNut's Avatar
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    Get a hold of some 1200 Keihin carbs or install some 44mm Mikunis and Hotseat intake manifolds...My vote is for the Mikunis...much easier to adjust and jet, IMO...also, they will hit harder. Also, for speed, run a 202 or 707 Nujet. I liked the 707 the best, in my heavier Virage.

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