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Mastermind meets the Dolmar 7900

Discussion in 'Chainsaw' started by Mastermind, Jan 16, 2012.

  1. Mastermind

    Mastermind Work Saw Specialist

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    They are probably the fastest saw in their size range......
     
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  2. nstueve

    nstueve Makita Freak!

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    Damn strait! Stock out of the box these are potent saws. Ported they are even better, obviously!
     
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  3. cgraham1

    cgraham1 I feel old

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    My 7900 has sure impressed me, I was just wondering how well they take to being ported. :)

    BTW, your Makita is on the way. Hopefully you get some use out of it. ;)
     
  4. Mastermind

    Mastermind Work Saw Specialist

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    I have a 6401 hanging on the rack here.......someday I'll play with it.
     
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  5. Adirondackstihl

    Adirondackstihl Flyz, Fuel & Fotos

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    Thawt U No Like The Udder Jermin Sawz?
    Dis Mean U Due My 7900 ?
     
  6. Mastermind

    Mastermind Work Saw Specialist

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    I hate Zama carbs.......Dolmars are fine saws.....
     
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  7. RiverRat2

    RiverRat2 Serio Tree Freak

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    yeah the Zama's pretty much suck
     
  8. cgraham1

    cgraham1 I feel old

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    I know I could search, but I'm gonna be lazy and just ask. So.... what's the deal with the Zama carbs? and can you swap them with some other carb without a bunch of custom fabrication? Thanks
     
  9. Adirondackstihl

    Adirondackstihl Flyz, Fuel & Fotos

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  10. Mastermind

    Mastermind Work Saw Specialist

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    The 7900 will accept a Walbro from a 372 with no mods needed I believe. :)
     
  11. cgraham1

    cgraham1 I feel old

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    I happen to have some 372 parts... image.jpg
    And a 7900...
    image.jpg
    And an appointment with Mastermind... So, what am I missing?
     
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  12. Mastermind

    Mastermind Work Saw Specialist

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    I'm working on fixing the pics in this thread....
     
  13. fordf150

    fordf150 ArboristSite.com Sponsor

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    Someday my 7900 will make the trip. For now I'm happy with the way it runs stock.
     
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  14. bryanr2

    bryanr2 Addicted to ArboristSite

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    Good God Im gonna need to get another one. :dizzy::ices_rofl:.
    Got the wheels turning..... starting to think about that brand new 6400 Dex is offering.:rolleyes:
     
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  15. bryanr2

    bryanr2 Addicted to ArboristSite

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    Clint- they are the King of the 70cc range. At 79cc, Id have to group them in the 80cc range though- and I think they hold their own pretty well in that class too. Many have considered the 064 to have had the best power to weight ratio in the past, that was until the 7900 came out. It is the reigning "power to weight" king.
     
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  16. RiverRat2

    RiverRat2 Serio Tree Freak

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    Time money and patience,,, oh and 7900 are great saws,,, Zama carbs are not the best

    Yes on all counts!!!
     
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  17. Jakers

    Jakers Owner - Arbor Jake's Tree Service, LLC

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    Would swapping the carbs out cure the hot start flooding issues? My 7300 is awful that way
     
  18. Mastermind

    Mastermind Work Saw Specialist

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    Good question.

    Lean issues are what I see mostly from the Zamas that I have issues with. Heck.....not all of them are any trouble either.
     
  19. Terry Syd

    Terry Syd Addicted to ArboristSite

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    All the Zama carbs I've looked at all have the same jetting - two .25mm jets. The jets can be drilled and the flow increased considerably. When a Zama is used on a bigger engine, they need a lot more flow. I've also tried blocking the auxiliary jet on a Zama and just used a drilled idle jet and with a stronger metering spring it may turn out to be an even better approach.

    I'm just starting on modding the HDs. They are a bit more difficult to mod as you have to pull the welsh plug and redrill the air bleed/transition holes (and drilling the body of the carb is permanent, you can't replace the jet like on the Zama if you go too far). Since the HD-12 seems to be a popular carb, it would be great to find out what size holes are used on the carb body, that way someone could drill their existing carb to the HD-12 specs. Although, the HD-12 was used on a 71cc engine, so even the HD-12 might benefit from a bit of tweaking to use on a 79cc engine.
     
  20. Gravedigger

    Gravedigger ArboristSite Operative

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    THANKS
     

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