This 650 Is Driving Me Crazy!!!
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  1. #1
    jetskigal
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    This 650 Is Driving Me Crazy!!!

    Ok, Took the advice from all and put the a restrictor in the return line right after the hose clamp where the return line attaches to the carb. The closest jet I could find laying around is out of a snowmobile .045. I zipped tieded it into place and now I have no fuel passing by the restrictor whereas when I initially started it before I had lots o' gas returning to the tank. Anyway, my problem is that before installing this I was able to start, idle, and low to mid throttle......it would just fall on its face (not enough fuel) to do anything for mid to WOT. Now that I have done this suggestion, I cant even get it to stay running. Now this has only been just in the garage after installing the restrictor. I checked to make sure there was fuel from pump to carb. I had the carb off to double check somethings so I thought it just needed to prime its self so I would start it and keep it running with the primer. I used the settings that I got from another thread about 44mm round body on a X2. If I recall it was like
    1 3/4 idle, 2 - 2 1/2 low, 1 1/2 -2 high (I have it wrote down in garage). Do you think these would be a good starting point on my 1990 650sx? I have no mods that would effect tuning. It ran and idled the other day before installing restrictor. PLEASE HELP, WOULD LIKE TO RIDE BEFORE OCT.
    Thanks ~Audrey

  2. #2
    seahorse1
    Guest

    Re: This 650 Is Driving Me Crazy!!!

    Audrey, the restrictor is not suposed to stop the flow of fuel into the tank, it is merely supposed to slow it down so the carb can use it before it returns to the tank.

    initieal carb setting should be...

    1 and 1/4 turns open on the high speed
    1 and 1/2 turns open on the low speed
    1 and 5/16 pilot.

  3. #3
    jetskigal
    Guest

    Re: This 650 Is Driving Me Crazy!!!

    From all of the other posts Ive read, people are using .30 - .040 jets for restrictors so I figured that going with a slightly larger .045 would work. It may not appear that there is much passing by the restictor since I couldnt get it to stay running much longer that 30 seconds (and that was by using the primer). I will give the carb settings a try tomorrow and see if I cant get it to atleast idle then fine tune on the water. I apprecieate all insight, it is just frustrating...........Im so use to a dirtbike or any other carb that is a "typical" jetted situation. I would love to just swap out with a SBN but not in the budget right now. Although, I do have a brand new, never used kehien with intake (not sure what size it is or how to tell other than measuring). It has a double butterfly valve so I would have to figure out how to rig up the throttle cable with some type of splitter...

  4. #4
    PWCToday.com Is My Home Away From Home Fletch's Avatar
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    Re: This 650 Is Driving Me Crazy!!!

    Ok, this might be a dumb question, but are you using a #45 pilot jet, or jet with a .45 cm hole in it? There is a big difference...

    In regard to your Keihin, that is not a second throttle butterfly - your top butterfly is a choke plate and can be replaced with a primer kit.

    Any idea what size Keihin it is? You're probably better off running it in lieu of the round body Mikuni assuming its a 38 or 40 mm...

    I think I have an extra manifold if you're interested in running the Keihin.

    -F
    "Come on guys! It's simple! Maybe you need a refresher course. It's all ball bearings these days!"

  5. #5
    seahorse1
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    Re: This 650 Is Driving Me Crazy!!!

    It's a BN 44, Fletch. I told her in another thread that it needed to be drilled out and rejetted, just as you and I were discussing before in the other thread.
    Those BN 44's stock, were made to run on the 550's, I think thats why she's having such a difficult time getting it dialed in for the 650, the engine is breathing more than the carb can supply the engine and keep it fed properly without modification.

    And yes Audrey, the restrictor needs to be .030

  6. #6
    jetskigal
    Guest

    Re: This 650 Is Driving Me Crazy!!!

    Fletch and Seahorse, Thanks for the replys! Fletch, I have to admit that I am not sure what size the keihin is as I do not see any print on it. I would have to use my micrometer then find the conversion rate for mm to figure it out..........right??? What I do know is that the hole is slightly smaller than the roundbody Im running now. I think the jet was .045 although I did not have a magnafying glass handy to confirm. I may be interested in your manifold if the one I have wont work. I purchase a box o' parts from a neighbor who raced older 550's so Im assuming it is probably set up for a 550. And now I know that the other flap on that carb is for a choke. I am so nieve with these carbs.....and I just hate not understanding them. So, do you diconnect one of the shafts and somehow block that off....or wait maybe a nipple to attach the primer too? Seahorse, I do appreciate your insight too! I just donot want to start drilling out non-removable jets on this carb if I do not have a back up ready to go. Please keep in mind, I road this jetski for 2 full years just a year ago with this same carb and no restictor in the return line, as that was how I purchased it. At that time it ran great, seemed a bit slow but it ran and was dependable. So that is why I have not drilled anything out and why I dont think that is my main issue as to why it wont run. But it could definetly be the reason why it seemed a bit slow on the top end.

  7. #7
    seahorse1
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    Re: This 650 Is Driving Me Crazy!!!

    Well, if it ran fine before with the same setup, then it maybe has trash inside of it, Was it already on the 650 when you bought it? or did you just buy the carb? How much do you know about the carbs history?
    I've ran dual BN 44's on 650's and 750's without needing to drill out the jets, but never a single without needing to be changed internally, they've always had way bigger than stock pipes also.
    But it is very strange that you were able to use that thing without a restrictor at all because they are designed to run in conjunction with the stock 550 rev limiter, and it works as a restrictor on non-modified boats unless it was previously modified internally, prior to you owning it..

    Would it be possible for you to take pictures of what you have set up so we can get a better look at whats going on under the hood?

  8. #8
    jetskigal
    Guest

    Re: This 650 Is Driving Me Crazy!!!

    yes, I will go and do that now. THANKS A MILLION FOR YOUR HELP!

  9. #9
    jetskigal
    Guest

    Re: This 650 Is Driving Me Crazy!!!

    I tried to embed pic in this post but they must be too big so here is the link to my photo album with the current carb and the Keinin:
    http://www.pwctoday.com/photopost521...0&ppuser=20301

  10. #10
    PWCToday.com Is My Home Away From Home Fletch's Avatar
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    Re: This 650 Is Driving Me Crazy!!!

    OK -- There'sa few things at work here.

    First off -- Sea Horse -- I don't think you were understanding what I was asking Audrey. A NUMBER 30 jet is not the same as a .030 restrictor. I wanted to make sure she wasn't running a number 30 jet, which would have an orifice size way smaller than .030 inches.

    Second -- the jet that you are running inline looks to me like a pilot out of a PWK dirt bike carb, or something similar. Usually those have a lot of little round holes at the tip where the fuel sprays... That may be an issue here.

    I'm noticing too from your pics that you still have your remote fuel pump in the ski. What I can't tell is whether otr not it is hooked up inline with the carb. While I don't think it would be a problem, it is definitely overkill, because the BN carb (and the Keihin for that matter) both have integrated fuel pumps.

    Third -- Seahorse is right - if that BN carb was originally set up for a 550, you will have to redrillthe body of the carb for it to tun properly on the 650. That's a pain in the ***, and if you've never done it before, it's kind of a risky operation, becaue if the hole is enlarged too much, there's no going back.

    As for your Keihin, that's a 38mm CDKII off of a 550SX with a reed motor. That would be a great carb to put on your 650 in lieu of the BN, until you could pick up a 44mm SBN Mikuni, or better yet,a 42mm Keihin.

    If you want to run the Keihin, I can get you dialed in exactly. Those came stock on the 650's from '91 to '93.

    -F
    "Come on guys! It's simple! Maybe you need a refresher course. It's all ball bearings these days!"

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