MillerModSaws and the PS-7910

[Adirondackstihl]

I just ported in my pants

 

[MillerModSaws]

All assemble with initial tune. I made a double d wrench to fit this carb I think it's gonna work pretty slick. I think it will stay right were it's at so I can tune in the cut. But i also slotted the end of the needle so who ever buys this won't haft to have the wrench.

 

[MillerModSaws]

So here it is. With the initial tune. I will pull the b&c of my 375xp to get this saw tuned and keep the new b&c for the comparisson. I need a camera man. I need to order up an adapter so I can put my stihl 28" bar on it too.

 

[drf255]

View attachment 404808 And here's a pic I will prob catch crap over. I am the first to admit I have a lot to learn but here I know the air and gas mix is in a gas form not a liquid but I like to run them under the faucet to try to understand how the trans are flowing. This one in particular the exhaust side trans I may pull the the edge closet to the exhaust a little more straight out on the next build. But like I said this is more me learning how each cylinder flows. And the directions my port work is aiming. On the port you see flowing. Both sides were head towards the intake when I started and you can see how I pulled the middle of the port around just a bit towards the center of the piston.

Ive been doing it too. What the goal of flow here, forcing the charge back towards the intake, laterally across port to collide with each other, or towards the exhaust port?

Does anyone do any assymetric work on the ports so the the flow is in different directions to compliment each other?

 

[Hedgerow]

Ive been doing it too. What the goal of flow here, forcing the charge back towards the intake, laterally across port to collide with each other, or towards the exhaust port?

Does anyone do any assymetric work on the ports so the the flow is in different directions to compliment each other?

Yes...
Husqvarna does it on the 372 from the factory..

 

[MillerModSaws]

Yes...
Husqvarna does it on the 372 from the factory..

O don't leave out the stihl heads buddy. The 361 is a good example of one port flat the other angled towards the combustion chamber.

 

[jar944]

Ive been doing it too. What the goal of flow here, forcing the charge back towards the intake, laterally across port to collide with each other, or towards the exhaust port?

Does anyone do any assymetric work on the ports so the the flow is in different directions to compliment each other?

Don't forget that in addition to efficient chamber filling, the transfers through directing the intake charge are used to "sweep out" the combustion gasses. Remove certain symmetric flow and you will have problems.

 

[MillerModSaws]

I've let the saw run now for about five minutes while tuning Yada yada. Let cool and I'm pulling about 180 comp. I was hoping for just a bit more.

 

[Andyshine77]

Are you using a good gauge? the cheap ones seem to blow out the O-ring at higher psi. I ask because my bone stock 7900 makes just over 180psi, I'm thinking you have a gauge issue.

 

[MillerModSaws]

Are you using a good gauge? the cheap ones seem to blow out the O-ring at higher psi. I ask because my bone stock 7900 makes just over 180psi, I'm thinking you have a gauge issue.

Yes I have a lisle and it's been good so far. I think. Lol.

 

[Andyshine77]

Yes I have a lisle and it's been good so far. I think. Lol.

Okay, in that case it may very well be reading a little low. Snap-On is the only gauge that I fully trust. So how does she feel so far?

 

[MillerModSaws]

Okay, in that case it may very well be reading a little low. Snap-On is the only gauge that I fully trust. So how does she feel so far?

I will let you know when I get to run here! I'm anxious to see if there's any good gains!

 

[Poleman]

Whats your elevation?? I'm at 4000ft and have to compensate. A 150 lb reading would be around 170 sea leavel. Use to drive me nuts trying to figure out how everyone else was getting such good and higher readings!!

 

[wigglesworth]

Okay, in that case it may very well be reading a little low. Snap-On is the only gauge that I fully trust. So how does she feel so far?

All I can afford is Snap-off's™...

 

[MillerModSaws]

Well v the lisle didn't hold up. Does this look better boys!

 

[MillerModSaws]

I'm ready but no camera man. I really gotta buy a video camera and tripod. Lol

 

[redoakman]

View attachment 405537 I'm ready but no camera man. I really gotta buy a video camera and tripod. Lol

lots of duct tape and something to tape it on lol

 

[MillerModSaws]

lots of duct tape and something to tape it on lol

That would work if I didn't use my phone right now as a video camera

 

[mdavlee]

I use my phone propped on something any more.

 

[cuttinties]

Cut a stick of wood off like you'd put in the stove. Then cut a slot to sit your phone.