Mastermind Meets The Dolmar 7900

[Normzilla]

Holy Smokes Norm, haven't seen a post from you in forever. How have you been?

I know right? I got burnt out of the other place. I'm back now breathe of fresh air fresh site

 

[bryanr2]

understand. Glad you've joined us here.

 

[Normzilla]

understand. Glad you've joined us here.

Me too, thanks to Randy.

 

[Stihlbro]

On exhaust height I build these on a lower exhaust for my loggers than I do for wood cutters. Here's my reasoning I've found with all else being the same so to speak a 104 exhaust height saw will run really close with a 100 degree exhaust saw. The difference is you have to work the 104 saw. The 100 degree saw does the work for you. Does that make sense. I'm not talking huge differences here but noticable. The 104 saw when felling will start in the cut much easier than 100 degree saw. So this all said let's here some thoughts.

I really like how you explained this. And it comes down to the users preference and what they are the happiest with. Let alone what you are cutting and what chain set up is.

 

[Backtroller]

Sorry if this has been answered already here, but would adding another deflector on the muffler on the 7900 - 7910 to make it a dual port help? I've already removed the cat and opened the existing opening just wondering what the pros think.

 

[mdavlee]

Stock saw not really. The cage is pretty well set up ideal for back pressure as is. It will sounds better.

 

[Backtroller]

Poleman carb and coil. Ports cleaned up, not ported yet....

 

[Backtroller]

Getting ready to assemble. However, I have to finish assembling Al's handi work on my 034 to 036 first though.

 

[mdavlee]

Might be worth it then. I never tried it on one that wasn't ported.

 

[Backtroller]

Thanks. I don't really want it obnoxiously loud if I can help it. I want it to breath though.

 

[Hedgerow]

I've built 2 more Just like it now. They're fun to run like that. He ran it with a 28" somewhere.

Iowa GTG..

Dam limiters. Hopefully Bruce gets us hooked up shortly! I liked how the Mutt ran. Awesome job on it. I would like to run it with a 28" bar. I ran it with a 20" and a square chain IIRC.

Just a sharp round chain.
That was well dulled shortly thereafter.
Sumbody put a frozen chunk of mud in one of them there logs.

 

[Miller Mod Saws]

Ok boys just got done porting a 7900 and 7910 so thought I'd show some pics and hope randy and Mike lee jump in here first et of pics is the before and after of the side of the lower trans. You can notice I have taken out just a little. This comes from studying randys pics of yhe 681 cylinder.

 

[Miller Mod Saws]

Here the red marks show what I'm gonna blend in. Now don't be fooled. I don't take a lot from these areas. Just blend them in smooth to try and help flow.

 

[Miller Mod Saws]

And some finish pics. This cylinder is at 100/128/81.

 

[Miller Mod Saws]

 

[Mastermind]

Keep going Carl. I'm working, and watching.

 

[Miller Mod Saws]

Here's a shot of the Roughed in 7900 exhaust so you can kinda see the difference.

 

[Miller Mod Saws]

Keep going Carl. I'm working, and watching.

Me too. I jut opened this up. You my friend know why it be! Lol.

 

[Miller Mod Saws]

I didn't use to touch the lowers. And then after seeing the 681 cylinder and the 7310 I played a little. One big difference I've noticed is when you open these lowers up the saw changes sound. It almost sounds like ya got a four barrel under the hood opening up. When I did my testing. I built a saw tore it back down and just changed the lowers. I'll see if I can find the vids but there is a noticable difference. Especially in the sound. Lol.

 

[Mastermind]

Me too. I jut opened this up. You my friend know why it be! Lol. View attachment 3838

Looks like an Echo.

Lots of gain in the transfers.