Dolmar 64xx/73xx/79xx series, smurfs and solo 665/675/681 thread

[Deets066]

Okay what's your thought process on that? I'm trying to learn and try different stuff.

I'm open to leaving it out too. I can do another exhaust if I mess this up.

I’m not saying it’s the only way or the best, but all of my mufflers are empty cans. I’ve never seemed to lose power from a more free flowing exhaust.

 

[mettee]

I don't want to discourage you because you are doing a good job and having fun, but your not exactly blazing new trails here with this saw.


Me too. Everything forward of the back plate is scrap.

I never thought I was blazing any trails Im just doing my exhaust differently.

Every combustion engine I've ever seen uses exhaust flow not exhaust diffusion, my thought process is that diffusing the exhaust in multiple directions isn't as good as giving it a path to a place it can expand and escape.

 

[mettee]

I'm not telling anyone how to do it. I'm. Just laying what I am doing out there. Once I try it, I'll report back, if it works great if not I'll tell yall.

 

[huskyboy]

My guess is that baffle is mostly to control noise. Deleting it improved throttle response and it seemed to run cooler. I tried just drilling holes in the baffle before I gutted it. Like it better gutted. Saves a bit of weight too. Both ways I had just the factory port opened up.

 

[Woodpecker]

I never thought I was blazing any trails Im just doing my exhaust differently.

Every combustion engine I've ever seen uses exhaust flow not exhaust diffusion, my thought process is that diffusing the exhaust in multiple directions isn't as good as giving it a path to a place it can expand and escape.

Expansion can work great. Pipes with huge expansion chambers work very well. Unfortunately there just isn't enough space for that concept to work within the confines of the stock muffler. I came to the same conclusion as Mason after fiddling around with mine and pitched the bird cage. Experimenting costs you little more than time though.

 

[RI Chevy]

Only way to really check it is through timed cuts. Stock, semi modded muff and full gut muff mod. Same bar and chain, same piece of wood. Same cutting style.

 

[huskyboy]

I tested stock vs modded with birdcage intact. It was 10% faster modded in the small pine I had available at the time. The saw likes to be tuned higher after I gutted it (it was too fat at the previous rpm I had it at) so I know it’s making more power vs with birdcage.

 

[RI Chevy]

Good deal Mason. [emoji106]

 

[mdavlee]

At one time I had meant to build a pipe inside a muffler on a Stihl that’s easy to work with and find the best size. Now I’m too lazy to even mod a muffler[emoji849]

 

[mettee]

At one time I had meant to build a pipe inside a muffler on a Stihl that’s easy to work with and find the best size. Now I’m too lazy to even mod a muffler[emoji849]

This is my mindset here as well. To try and create a pipe effect within the stock muffler. Hell, I'm not going to lie, when I get my Tig I'm making a pipe that fits in the stock pipes location.

If any of you look at the stihl mufflers they have a baffle in them that has a shape very similar to what I'm trying to do. And they are known to hurt power when they are removed(read this in a recent thread may only pertain to one stihl saw).

I really feel like cut times are subjective. Too much human influence to make them quantitative. A saw dyno would be the best way. But we are splitting hairs at that point.

 

[wcorey]

And they are known to hurt power when they are removed.

Curious as to the source of this information...

 

[mettee]

Curious as to the source of this information...

Let me find it for you.

ETA: I can't find it. But it was in a recent stihl thread and the pics showed the baffle out and I believe they mention putting it back as it hurt more than helped.

I'm trying to learn so if I miss read or that's bad info please speak up okay?

 

[mdavlee]

Curious as to the source of this information...

Red Bull and mustang Mike had that result on a couple saws that weren’t ported

 

[T.Roller]

Let me find it for you.

ETA: I can't find it. But it was in a recent stihl thread and the pics showed the baffle out and I believe they mention putting it back as it hurt more than helped.

I'm trying to learn so if I miss read or that's bad info please speak up okay?

You can't believe everything you read lol

 

[mettee]

You can't believe everything you read lol

I should have explained what I read better. But you are right.

 

[huskyboy]

Its just starting to come around... it’s like a light switch gets turned on when a saw gets broke in. I had it tuned past the limiter in this video. Wood was some sort of seasoned maple I think.

 

[RI Chevy]

Nice Mason. I would send it off for a full port job.

 

[huskyboy]

Would be interesting to see what a full ported one would do. If I get another... maybe I will send it out. This one runs well enough I’ll probably leave it alone.

 

[psuiewalsh]

There is a warhawk 73cc deal of the day for $30. Anyone tried one on a 6400 ?

 

[Wilhelm]

Dolmar PS-7310, other than mild muffler mod (SLR removed, outlet enlarged) factory stock and well worn and misused by previous owner.
Clutch drum was black from slippage, it got replaced. I still have to renew the weights as they seem to slip under high load (hot drum & clutch cover, my other large frame Dolmar's don't have that issue).
36" B&C, 3/8" 115DL , chisel round filed , oak

I usually don't encounter logs large enough to justify using my 36" B&C setup, so I opt to go with aggressively set loops on my main 20" B&C setups - one heck of a ride, always makes me grin ear-to-ear.

This was fun, fairly worn Dolmar 099 (Oregon LGX) loop that became a play chain.
I shouldn't have pushed down so hard, would have kept higher in cut rpm's.

IMHO, lots of power in these saws even in stock form.