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Mastermind meets the Dolmar 7900

steve316

steve316

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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
 
Mastermind

Mastermind

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Back in the day's when Ed/EHP was a member here the 359 were all the rage, a fire wood cutters dream, they'd out cut stock 372's 440's in 20" wood all day long.
Ed was a big help in this 7900 build. :)

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

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

Mastermind

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

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.

It looks like you have a good runner....however I think a reallly good built 372 or 440 will beat it.
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:
 
Andyshine77

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

Jon1212

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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.
I couldn't have said it better myself. If you stick to one way and only one way, you never learn anything new.:cheers:
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!!!!
 
bryanr2

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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.
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
 
cbrduckdog

cbrduckdog

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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
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.
 
bryanr2

bryanr2

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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.
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).
 
cbrduckdog

cbrduckdog

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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:
 
Mastermind

Mastermind

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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:
 
Mastermind

Mastermind

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