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Mastermind meets the Dolmar 7900

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

  1. steve316

    steve316 ArboristSite Operative

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    compression

    Randy;Did you check the compression before and after,mine is stock and on my gage it is 181psi. I had my gage calibrated so I feel this is half way correct and wondering what type of gain one could exspect with a pop-up plus .010 off the chamber.thanks for putting a great post. Steve
     
  2. Mastermind

    Mastermind Work Saw Specialist

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    Ed was a big help in this 7900 build. :)

    I doubt I raised the compression much after raising the exhaust port.

    I'll check specter's saw tomorrow, Brian's is gone....
     
  3. Andyshine77

    Andyshine77 Tree Freak

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    Ed's helped me out many, many times, he's a standup guy in my book.
     
  4. bcorradi

    bcorradi Arboristsite.com Sponsor

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    It looks like you have a good runner....however I think a reallly good built 372 or 440 will beat it.
     
  5. Mastermind

    Mastermind Work Saw Specialist

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    Yes he sure seems to be. He always gives me a good clear answers when asked. I would say he's forgotten more about building two strokes than I may ever learn.

    In this size and type of wood it's a close race for all these saws. I enjoy running a 7900 as they do seem light and handle well. I don't like the ass backward kill switch though. :laugh:
     
  6. Jwalker1911

    Jwalker1911 Addicted to ArboristSite

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    Looks to me like you build a heck of a saw
     
  7. Mastermind

    Mastermind Work Saw Specialist

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    A lot of guys around here do. I just take my time and try hard to keep an open mind. I feel like forming concrete opinions about things stops our growth.....a new idea can't be grafted into a closed mind.
     
  8. Andyshine77

    Andyshine77 Tree Freak

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    I couldn't have said it better myself. If you stick to one way and only one way, you never learn anything new.:cheers:
     
  9. Jon1212

    Jon1212 Riff Raff Fart Knocker from other Forum's.

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    And that Ladies& Gentlemen is exactly how I ended up with my ported, and modded MS 390 by Randy (Mastermind). I've used it before, and after in front of my oldest boy's FIL, and he thought it was a different saw..........LOL!!!!
     
  10. bryanr2

    bryanr2 Addicted to ArboristSite

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    Nominated for quote of the year. Well said.
     
  11. bryanr2

    bryanr2 Addicted to ArboristSite

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    We will know soon enough. I've got a 044 10mm in Mastermind's shop as we speak. I cant tell ya if it's on the bench or the floor, dut I do know it's in the door.:blob2:

    stevn
     
  12. cbrduckdog

    cbrduckdog ArboristSite Member

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    We can play, I am just south of you in Loudon County and the 7900 is at the post office waiting for pick-up. Would love to see how it performs.
     
  13. bryanr2

    bryanr2 Addicted to ArboristSite

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    Sounds good. Ive got the 6401 sitting in the garage and the 7900 kit and HD kit sitting in the house. After running Randys 44/46- I cant wait to get mine back. Dont know if to do the Makita, 288, or 2095 next. prob the kita so I can get these boxes out of the house.

    What part Loudon County are you- Im in West Knox (Walker Springs/ Cedar Bluff area).
     
  14. cbrduckdog

    cbrduckdog ArboristSite Member

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    Old thread new info: I have cut a lot of wood with this saw which was ported by Randy. It has the slab piston in it. I have always run it with an 8 pin and 24 inch bar. I just like the feel of the 8 pin with the 24 inch, personal preference I guess. I tried it with a 32 inch bar with skip tooth Stihl RSC which put a huge smile on my face, held 11,000+rpms in the cut, I did change it to a 7 pin but should have seen what it would do with the 8 pin. Oh well something to try next time.
    Anyway Randy Thanks! :rock: I have not done this saw justice in reporting how good a job you did. If I find another 7900 I know who has the recipe! One SOB of a saw! Oh how do I get a sticker?:laugh:
     
    cgraham1 and 7sleeper like this.
  15. 7sleeper

    7sleeper Addicted to ArboristSite

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    Always good to get a long term feedback! Better than some short term enthusiasm!

    Rep sent!

    7
     
  16. Mastermind

    Mastermind Work Saw Specialist

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    I just need your address.......that reminds me...........I am almost out of stickers again. :msp_wink:

    When you ran that thing at the GTG I was eating a hotdog.....I thought "what in the hell is turning that much RPM in the cut?".

    Seeing that saw run that strong helped me make some decisions on other builds we have in the works...that's for sure. :msp_sneaky:
     
  17. Mastermind

    Mastermind Work Saw Specialist

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    I sure wish I had a newer video of that saw............ :msp_thumbup:
     
  18. redoakneck

    redoakneck Addicted to ArboristSite

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    How much improvement over stock????
     
  19. Hedgerow

    Hedgerow HACK

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    40% of course...
    :laugh::laugh:

    Maybe 50!!!

    :msp_thumbsup:
     
  20. cbrduckdog

    cbrduckdog ArboristSite Member

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    I will see if I can help with at video. Give me a couple of weeks its hot but I am also traveling with work. BTW I have a 32" bar on order.
     

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