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  1. #1

    Down to the wire, time to tune it up on the water.

    Finally finished my total rebuild, in and out. '93 Sl 650. I've double checked everything again and again. Everything is new or rebuilt. Carbs, etc etc. New fuel lines, triple fuel pump, autocock removed, leak-down test. Everthing is done! I'm sure!!! I've dry fired it up and it takes right off. Only a few 7 sec. runs.

    The Low speed screws are all 1/4 turn out Plus a tad to be sure I'm not lean
    The High Speeds are 7/8 mag, 3/8 center and 5/8 PTO (all plus a tad, again to make sure I'm not lean!)
    Pop-offs are all correct, between 10-16 lbs
    Also, I have added a Polaris stock Tach to the dash!

    Here's where I need you guys, one more time!

    FIRST..I'm going to take it to the local lake, back the trailer into the water and fire it up. I'm going to then adjust each low/speed one by one until each gives me the highest rpms and the idlel screw in and out to go for 1200-1300 rpms. I'l do this back and forth with the low speeds several times. I'm going to go for the highest rpm each time, MAKING SURE that the rpms are constant, since I've read that they may actually fluctuate slightly at the absolute highest, but that will likely be a little lean. I'm going to make sure I'm NOT too far off from my original settings 0f 1/4 turn out since that may indicate a problem elsewhere within the carb!

    NEXT, i'm going to then take it off the trailer and see if I get a clean acceleration from idle. If I do, then I go to the high screws. This is where I get a little confused. If I don't get power/acceleration at higher speeds, how do I know what carb may need adjusting?

    I know I want to check the piston wash and I know what to strive for, but I obviously can't adjust a carb while I'm riding at high speed so what's the actual process for the high speed screws! I just want to get it right without burning a piston. I've put a lot of work into this thing!

  2. #2

    Join Date
    Jun 2008
    windsor ont
    start with the high speeds rich and read the plugs after short runs.adjust carbs accordingly and make longer runs until plugs stay nice and brown

  3. #3
    She likes the bike. But the ski gets her wet!!!! xlint89's Avatar
    Join Date
    Oct 2006
    Cleveland OH
    LT, you don't need to turn the low speed screws out any to prevent it from running lean. Low speed screws are just for a smooth idle and take off. Those will not cause a hole. I'd set them to spec.

    The low speed screw adj test you propose is good, but remember to make your idle speed a tad higher than what the book calls for. (in water speed usually around 1200 RPM, you'll want to adj screws around 1500-1600 RPM for the test)

    For high speed, use your tachometer. If it reaches peak RPM and falls off, you're either running lean, or extremely rich. Do a plug chop to verify which it is. Wet would be rich and white would be lean.

    You're looking for around 6300 RPM max and a nice chocolate brown color on the plug.

    Take your plug wrench with you as idleing back to the dock will not give you an accuarte plug reading. You need to do a short WOT run and pull the lanyard to check the plugs.

    Good luck

  4. #4
    That's what I'm looking for. Thank you! I've got 14 grandkids that have watched me completely redo this machine over the last 4 months, in and out, and I just want a nice running, safe, ski for them! Thanx again xlnt89!

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