Mastermind Meets the Dolmar 120si

[Mastermind]

Good looking Dolly here. I really admire the classic looks of these saws.

The offset combustion chamber makes for a strange looking piston. This one is going in backwards too. The ring ends make it impossible to widen the uppers without spinning it around.

I'm a firm believer to modifying the uppers. I feel like the transfers are key to a strong saw. After all, that's how the fuel reaches the combustion chamber.

Just standard stuff from here on out.

We ended up with 162° exhaust duration, 22° BD, and 154° of intake duration with .024 squish.

Here's the saw as it was when it got here. The chain isn't very sharp and it's a bit fat....but this is how I received it so....

[video=youtube;T5DtlnW7fy0]http://www.youtube.com/watch?v=T5DtlnW7fy0&feature=g-upl&context=G2541256AUAAAAAAAAAA[/video]

I've ran it some since finished, but it needs a little carb or vent work. It gets a bit lean after a few seconds so I'll be doing some tinkering before it's ready for wood. I will say this though, it's a much different saw now.

 

[Stumpys Customs]

Good job Randy.

I think the third saw I ported was a 120si. I didn't pay attention to the ring ends & went a lil far on the uppers. I wish I woulda done the simple thing like you did & just put the pston in backwards. I ended up relocating the top ring & just running one ring. My stepdad has the saw now. It flat pulls. Not sure what I did right on it but it's hard to beat.

 

[o8f150]

nice job as usual randy,, it sounds good

 

[chopperfreak2k1]

cool, what an odd lookin piston.

 

[Mastermind]

Good job Randy.

I think the third saw I ported was a 120si. I didn't pay attention to the ring ends & went a lil far on the uppers. I wish I woulda done the simple thing like you did & just put the pston in backwards. I ended up relocating the top ring & just running one ring. My stepdad has the saw now. It flat pulls. Not sure what I did right on it but it's hard to beat.

The simple stuff sorta blows my mind sometimes. This sort of thing I've learned to be on lookout for these days though.

nice job as usual randy,, it sounds good

The video is of it stock.

cool, what an odd lookin piston.

Weird ain't it Roger????? :msp_biggrin:

 

[o8f150]

was the vid before you ported it???,, i didn't watch the whole vid before until now

 

[o8f150]

The video is of it stock.

when i made my first comment i only watched the first 10 seconds of the vid,,, dang i feel bad and look stupid,, it sounded pretty good at first

 

[Stumpys Customs]

I like the angle on the uppers too. Should help scavenging. I noticed this doesn't have the step in the ex floor. Or am I seein things.

 

[Mastermind]

when i made my first comment i only watched the first 10 seconds of the vid,,, dang i feel bad and look stupid,, it sounded pretty good at first

LOL Scott I probably shoulda but that video at the beginning of the post.......huh????

 

[o8f150]

LOL Scott I probably shoulda but that video at the beginning of the post.......huh????

yep,,, i got all confused

 

[Mastermind]

I like the angle on the uppers too. Should help scavenging. I noticed this doesn't have the step in the ex floor. Or am I seein things.

Not enough meat there. Or in many other spots. I couldn't widen the ports as much as I normally do either. I made a cut with it after porting and it came out well. Now to figure out why it's leaning out.

 

[Stumpys Customs]

I found the carb on mine to be real finiky to tune. I finally found a sweet spot.

 

[pioneerguy600]

Looking good Randy, nice work on the ports and piston. I cut more wood with the 120`s than any other saws I have owned, ran them from 1985 -1991 and cut 400 cord or more a year with them.
I just went back to watch the vid on the as delivered saw, it better work a hellava lot better when you are through with it, that saw was real rough in that vid. and I know those saws real well.

 

[blsnelling]

Good looking work as usual Randy. I'm shocked how strong the saw looks stock. I'm anxious to see the after vid.

 

[bryanr2]

What a great lookin saw! Sorry I sent it with a dull chain. I liked it b4 I dropped it off. Can't wait to see it run ported and tuned. How would you rate the quality of this saw model compared to other high 60 low 70cc saws?

 

[Mastermind]

Looking good Randy, nice work on the ports and piston. I cut more wood with the 120`s than any other saws I have owned, ran them from 1985 -1991 and cut 400 cord or more a year with them.

They are a solidly built, well thought out saws it seems. I really like the way the muffler opens up. Much better design than many we see here.

Good looking work as usual Randy. I'm shocked how strong the saw looks stock. I'm anxious to see the after vid.

I hope the saw looks as good in the next video as it feels Brad. It seems very stout now. I'll be out of the shop tomorrow till dark, but I may get it squared away when I get in.

 

[Mastermind]

What a great lookin saw! Sorry I sent it with a dull chain. I liked it b4 I dropped it off. Can't wait to see it run ported and tuned. How would you rate the quality of this saw model compared to other high 60 low 70cc saws?

To me this series of saw is as good as any that are made. I think it's a shame the Dolmar doesn't have the dealer base in this area to compete with the big two. :msp_sad:

 

[pioneerguy600]

They are a solidly built, well thought out saws it seems. I really like the way the muffler opens up. Much better design than many we see here.

They were a high performance saw out of the box, all mine were woods ported but I have never run a popup in one, just shaved the base and adjusted the squish.

 

[Mastermind]

They are a solidly built, well thought out saws it seems. I really like the way the muffler opens up. Much better design than many we see here.

They were a high performance saw out of the box, all mine were woods ported but I have never run a popup in one, just shaved the base and adjusted the squish.

The exhaust is at 160 degrees duration stock, so they planned on em turning some rpm. :msp_scared:

 

[bryanr2]

I cant find alot of info on them. I think there were 3 varieties- 120, 120 super, and 120si. This one came up on a Craiglist ad as "Sachs Dolmar 20 saw". Price was right. Called the guy he had to go look in the shed to get me the model #. Read what I could over night, watched a couple videos, ran it through a piece of wood off the back of my truck next day, and brought it home. Gentleman was a older man and it had gotten to heavy for him. He had picked up a 55 rancher and was gonna do his cuttin with it. Sold me the Dolmar to cover what he paid for the used 55. It instantly became my one of my favorites. Grab it more than any of the other 70cc saws I have. That may change after Mastermind does my 044 next. We'll see. I know that 44 he let me run last week was a monster!