Author Topic: Dolmar 7900 Porting Info  (Read 4074 times)

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Offline Cut4fun .

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Re: Dolmar 7900 Porting Info
« Reply #60 on: June 30, 2014, 11:39:55 am »
Redprospector had this to say long ago. Romeo & I did a side by side comparison between a stock (broke in) 7900, and the brand new stock 681 (actually it's very first cuts), same bar & chain in (if I remember right) a 21" log. The Solo out cut the Dolmar by almost a second a cut pretty consistently. That's not that big a deal when you're out in the woods bucking logs, but it is braggin' rights.

Both were loggers and racers and no how to run and time saws correctly.  ;)

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Offline KilliansRedLeo

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Re: Dolmar 7900 Porting Info
« Reply #61 on: June 30, 2014, 12:01:01 pm »
Going to find out if I can get a 681 C/P kit from Solo. Wish me luck!
"When the people fear the government...you have tyranny....When the government fears the people....you have liberty"

Thomas Jefferson
1743-1826

Offline Cut4fun .

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Re: Dolmar 7900 Porting Info
« Reply #62 on: June 30, 2014, 12:04:14 pm »
Brad had the stock 681 numbers.  no stock OEM 7900 timing numbers found yet.

681 OEM
Exhaust 105
Transfers 131
Intake 81




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Online srcarr52

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Re: Dolmar 7900 Porting Info
« Reply #63 on: June 30, 2014, 12:11:31 pm »
Never checked but there has to be port timing difference IMO.  The stock 681's I ran were so strong and it cant be because of just 1mm more stroke. Just my guess.

I agree add what you said to the fact that you need a 1.5mm spacer to make the NWP BBK Dolmar jug work on the 681. There must be some sort of timing difference!

1mm difference in stroke will cause quite a difference in port timing.  Putting a larger stroke in a saw without changing port heights will cause longer exhaust and transfer duration, shorter intake duration.

Offline Mastermind

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Re: Dolmar 7900 Porting Info
« Reply #64 on: June 30, 2014, 01:27:23 pm »
I use Loctite 518.

The parts have to be dead clean......and it needs to cure for 12 hours.

Have you or anyone else tried 515?  similar stuff a bit easier to spread out. That is what echo recommends on some of their crankcases along with threebond.

Yeah Nate......I tried 515 too. I had some base leaks with it. That's why I only use 518 now.
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Offline farmboy

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Re: Dolmar 7900 Porting Info
« Reply #65 on: June 30, 2014, 08:07:18 pm »
Stump's timing #'s stock 7900 http://www.arboristsite.com/community/threads/project-stumpbroke-makita-7900.197324/
Ex. 150*
Tr. 96*
In. 156*
BD 27*
Sq. .021
Tim,
I knew Baileys used to carry the 1.5mm spacer separate I found my link I had saved PN: 68115 NLA separate now.
Shep

Offline aclarke

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Re: Dolmar 7900 Porting Info
« Reply #66 on: June 30, 2014, 09:11:06 pm »
We compared the 681 vs 7900 port timing numbers when we had the 681 build off that Romeo (Sean) participated in.  He and Redprospector and myself checked timing we came to the conclusion the jugs were the same.  It is my understanding that Solo designed the 7900 for Dolmar. Wasn't there a few other models that were rebadged Solo saws in the Dolmar line up?? Adam

Offline KilliansRedLeo

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Re: Dolmar 7900 Porting Info
« Reply #67 on: June 30, 2014, 09:58:49 pm »
Yes, solo 665=6400, 675=7300, 681=7900
"When the people fear the government...you have tyranny....When the government fears the people....you have liberty"

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Offline Mastermind

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Re: Dolmar 7900 Porting Info
« Reply #68 on: June 30, 2014, 10:27:11 pm »
How's it going Adam?

681 has the decomp in the top.......but the timing numbers are the same.
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Offline KilliansRedLeo

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Re: Dolmar 7900 Porting Info
« Reply #69 on: June 30, 2014, 10:40:45 pm »
Thank you Randy, you saved me 246$.

Thanks for your open communication
KilliansRedLeo
Tim Holcomb
"When the people fear the government...you have tyranny....When the government fears the people....you have liberty"

Thomas Jefferson
1743-1826

 

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