Bought Vmax without V-boost

Discussion in 'Carb/Tuning' started by Eckhoff, Feb 8, 2019.

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  1. Feb 8, 2019 #1

    Eckhoff

    Eckhoff

    Eckhoff

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    I bought a 86 Vmax and have restored a lot of the bike. The V-boost was removed when I bought it. I didn't know a lot about these bikes so I didn't think much of it.
    The bike didn't really idle well, but ran good when giving throttle. The original air box and filters was still used.

    My question is, what should I do. I want to have a bike that can idle and run more smooth, not just on/off when it comes to power. What are my options here? I don't have the old V-boost to this bike.

    Seems like it's impossible to sync the carbs also.
     
  2. Feb 8, 2019 #2

    Fire-medic

    Fire-medic

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    Try Sean Morley one2dmax@aol.com of Morley's Muscle (banner ad on website) for the parts you need, it's not gonna be cheao wherever you get the parts. Do you have the motor for the VBoost, and the cable still-on the bike? There are electrical parts too. Look under the left scoop, is there a round disconnect male/female plug? That's part of it.

    Is the manifold assembly there, just not with the VBoost butterflies installed? In their place would be a pair of tubes. Do you have a rubber hose going into the oil fill plug for the engine/transmission? It should run from the airbox area, and is a breather for the crankcase venting system. That would suggest you have a Dynojet Stage 7 jet kit but that the OEM airbox was retained. Are there individual pod filters in the airbox, or is it the stock OEM long oval air filter?

    You won't be able to properly synch the carbs because you need to be able to isolate each carb from each other to set it. Either look here for the manufacturer's instruction sheet for the Stage 7 Dynojet kit, or look at their website and compare what you have to the sheet.
    http://www.dynojet.com/pdf/4716.pdf Note the sheet says, "USA models only." I think the Japanese version of the VMax eliminated VBoost.
     
  3. Feb 8, 2019 #3

    Eckhoff

    Eckhoff

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    I don't have to motor for the VBoost, the round plug under the left scoop is not there.

    The manifold assembly is there, but like you said it's a pair of tubes between them. There are no rubber hose from the oil fill plug, just the regular cap. Stock OEM long oval air filter yes.

    The bike is a US model, imported from Florida in the 90s.
     
  4. Feb 8, 2019 #4

    one2dmax

    one2dmax

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    I will have all the parts you need. The round connectors are on the black control box and servo motor both of which are removable.
     
  5. Feb 11, 2019 #5

    Eckhoff

    Eckhoff

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    Is it strange that I have one of the Dynojet kits but still has the original air filter?

    And is there a way to figure out what kind of Stage the kit is? I guess the carb tuning is different for the different kits?

    I am still not sure if I want to buy the Vboost system or just try to make the best of what I have right now.
     
  6. Feb 11, 2019 #6

    MaxMidnight

    MaxMidnight

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    The attached shows the different needles.

    If memory serves well the top is OE, then S1 and then S7.

    I'm sure if I have that wrong some kind person will put us right?
     

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  7. Feb 11, 2019 #7

    one2dmax

    one2dmax

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    You are correct Steve. Here's a more comprehensive picture
     

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  8. Feb 12, 2019 #8

    CaptainKyle

    CaptainKyle

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    I have a complete boost system that I just pulled off a bike.
     
  9. Feb 12, 2019 #9

    inspecto

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    Hint, hint...
     
  10. Apr 23, 2019 #10

    Eckhoff

    Eckhoff

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    So I finally had some time to start working on this again, and I need to find a solution.

    It doesn’t seem to be a Dynojet kit on this bike like I thought. The needles and the jets are all original. The jets are 170 and 90 so also original. It looks like the slides have been drilled, the hole is 3,5 mm. And as you can see on one of the pictures, it looks like the air cut off valves for some reason have been plugged with sealing.

    So I’m not sure what would be the best solution here. Maybe buy the Vboost system but that’s a bit expensive. Other alternatives?
     

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  11. Apr 23, 2019 #11

    one2dmax

    one2dmax

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    While you're at it i'd clean out the silicon from the covers
     

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