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  1. #1

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    calling the carb experts......

    Question for the carb tuning experts. I have a 95 venture 701 that is bone stock. Removed the choke plates and added a primer. Got rid of the extra screens on the stock flame arrestor cover. It now seems to be a little lean...(I was expecting it). Was wondering if I need to go up one size on the jets? Anyone with any experience in this area with the twin carb 701's? I have a 760 raider also that was recently overhauled with .25mm oversize pistons, otherwise stock, that I did the same thing to. Any suggestions on either? I know this has been done countless times, just looking for suggestions to make the tuning easier. Thanks in advance for any tuning suggestions.


  2. #2
    john zigler's Avatar
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    You will need to change your needle arm springs, to lower pop off pressure.

    You "may" get away with just upping the low let.

  3. #3
    This is how I run a jetski shop in the desert nmpeter's Avatar
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    I'd suggest running the flame arrestor unless it's a strictly race ski.

    to really tune it you need to get the wfo setup first, then work your way down.

    plenty of how to's on the forum on this point..helps to have a couple of clean plugs for plug chops.

    all stock?..might get by with some low/high adjustments depending on your situation.

  4. #4
    Happily Self-Employed WFO's Avatar
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    I havent done a lot of over-stock work on the smaller twins, but on the 800s we up the high speed jets when going F/As. Here lately because of the crap fuels, we pretty much re-jet on all our in-house engine rebuilds.

    You may be able to get away with just adjusting the screws, but you will need a tach and make WOT passes and adjust with that. Usually if you are at 2 1/2 turns on a screw, its time to go up in jet size

  5. #5
    Myself's Avatar
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    On an otherwise stock 701 62t you should be able to adjust it out without changing jets. Try 1 turn out on both lows 1 turn out on mag high and 1 5/8 turn out on pto high. Then do a plug chop and post back.

  6. #6

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    I put the two extra screens back in each flame arrestor pack, set the lows and highs to factory spec, and took it out yesterday. Has a bad bog from idle to 25% throttle.....have to feather it to get it to WOT. Gonna pull the carbs and check em, and check for correct spring, and try that setup from Myself. BTW, compression is 153 mag, 148 pto, so no motor damage from running lean. I will check back.

  7. #7
    Myself's Avatar
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    Sounds like the typical lean hesitation. Open both lows 1/4 turn and see if it clears up.

  8. #8

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    I pulled the carbs and checked to make sure they were clean. I changed the springs to 95gr and set the screws to the setup Myself suggested. Ran pretty good, but would load up after a few seconds of idle. Ended up with these settings: L 3/4 turn, H 1 turn mag side, 1-5/8 pto. I may still adjust on it, but it needs only slight adjustment, I didn't realize how sensitive these carbs were. It loads up slightly after a long idle, and you can just about feel the carb transition from low to high circuit, but plugs look pretty good, and my wife is happy with it!

  9. #9
    Myself's Avatar
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    1/8 turn makes a lot of difference. Happy wife, happy life. My wife used to really like her Waveventure . Then I rebuilt a GP1200 and now she won't go back to a 3 seater.

  10. #10
    Stock exhaust? On my b-pipped f/a'ed 701 superjet I ran:

    Bn38 dual carbs
    Ls- 1 turn
    ljet- 75
    hjet- 135
    hs- 1.25
    spring- 115(gold)

    ...and it was a little too rich down low fouled plugs after a weekend. With 95spring and it was flatulating rich and worse.

    I then dropped the ljet to 70 kept the 115g and it woke up with crisp response down low. Now tuning for top end and with a 137.5 jet. I may have to go 140hjet or even a 72.5 ljet. If you are turning the screws more than 1.5 turns then you need to rejet and go up. .5 turns then go down in jetting. The low screw has less affect on the low end then the high screw does on the high end.

    What jets springs and setting are in there now?

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