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Project RVF400 Tyga Maggot Full System Tuning

Discussion in 'Other Projects - Other Bikes (non 250's)' started by ZippiT, Oct 16, 2017.

  1. ZippiT

    ZippiT Active Member

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    Hey guys, first post on here

    I have recently bought an RVF400 with a full TYGA exhaust system, with a Maggot muffler. I have cleaned the carbs, synced, and fitted new rubber boots.

    The bike runs fine, up until 4-6th gear, where the mid-range flat spot becomes apparent. It's worse on the highway or going above 80KM/h with wind gusts, making the bike feel like its about to die.

    The bike was running:
    #108 Mains
    #35 Pilots
    1 5/8th turns out
    1x 0.5mm washer under each needle

    Basically the carbs were stock, I tried changing to:
    #110 Mains
    #35 Pilots
    2 turns out
    2x 0.5mm washer under each needle

    The bike runs no better, if not worse.

    Is there any suggestions to fix this problem? Does anyone run a Maggot and are able to post what setup they have?

    Thanks in advance
     
  2. Linkin

    Linkin The Apprentice Premium Member Dirty Wheel Club Contributing Member

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    You've gone up a main jet size and the problem got worse, my guess is that it's too rich.

    It would help to know the condition of the spark plugs and air filter.

    Also is there a fuel filter fitted? Could be starving for fuel

    As an addendum, bikes often run rich with less restrictive exhausts because of valve overlap, it draws more air/fuel mixture from the combustion chamber into the exhaust
     
    Last edited: Oct 16, 2017
  3. kiffsta

    kiffsta Administrator Staff Member Dirty Wheel Club Contributing Member

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    Tyga recommend 112 for the front and 115 on the rear pots and. 1 x 0.5 washer under the needles, maybe set your mix screws back to 1 5/8 then work up in 1/8 turn increments
     
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  4. ZippiT

    ZippiT Active Member

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    Spark plugs and air filter are used but new. No fuel filter, straight from petcock to carbs. Flat spot is only really noticeable at speed, bike starts to break down. Down low, bike pulls perfectly up to 14.5k, but once speed is achieved, (70-80+KM in 3rd+ gear) the bike starts surging and playing up.

    Will give it a shot, I have also emailed TYGA to as what they suggest

    Thank you for the quick responses.
     
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  5. my67xr

    my67xr Bike Enthusiast Staff Member Premium Member Contributing Member

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    Surging at higher speed's is lean in the main jet, don't adjust the needle clip from standard position/setting as per kiffsta's post
    Should only need to adjust mixture screw's for idle and up to 1/4 throttle
     
  6. Murdo

    Murdo The Good Doctor Staff Member Premium Member Ride and Events Crew Contributing Member

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    Welcome to the forum.
    Sounds like it is running out of fuel. Runs fine at slow speed but empties the fuel bowls quicker than the fuel can fill them as the revs rise. Will never be able to tune it without full fuel bowls.
    Have you got full flow from the fuel tap? Are there any small mesh filters in carb bodies before the needle and seats?
     
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  7. Linkin

    Linkin The Apprentice Premium Member Dirty Wheel Club Contributing Member

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    That would also fit with it getting worse with larger jets = empties the bowls faster.
     
  8. ZippiT

    ZippiT Active Member

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    Cheers,

    Fuel tap is still on vacuum operation, but it works perfectly fine (have tested, no leaks as well.) bike gets enough fuel around town at nearly any given RPM, just stutters at higher speeds, worse when wind is hitting the front.

    I don't think thee RVF has inset mesh filters in the carbs.
     
  9. Wozza

    Wozza Active Member

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    try reducing the plug gap a tad and see if it improves...coils might be marginal and getting snuffed out under load conditions when hot...
     
  10. my67xr

    my67xr Bike Enthusiast Staff Member Premium Member Contributing Member

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    Try a little bit of choke in the higher rpm's and see if it smoothen's out a bit, engine won't want to rev as much after a little while though
    If it help's then you need bigger main's
     
  11. ZippiT

    ZippiT Active Member

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    Taken the carbs off already, given them a once over. Got some jets coming tomorrow, will try 112F and 115R first and see what happens. Checked the vacuum hose and cut down old ends just in case
     
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  12. my67xr

    my67xr Bike Enthusiast Staff Member Premium Member Contributing Member

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    Don't forget to take a shim out from under the needle's too while the carby's are off, just needs the 1 shim under each
     
  13. GreyImport

    GreyImport Administrator Staff Member The Big Cheese Contributing Member

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  14. ZippiT

    ZippiT Active Member

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  15. ZippiT

    ZippiT Active Member

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    Just an update;

    Got some 112s, 115s, 118s and some 120s, I put the 115s in the front, and the 118s in the rear to just start a base line, bike runs much better, still some sputter but way less.

    May try upping to 118F and 120R and see if it just smooths it out a little more.
     
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