Upper transfer angles

[jacob j.]

We've done about 20 saws in the last two weeks.

Hopefully one of those was my "Woods Boss" Pro Mac 610 with the Homelite XL-AO piston.

 

[Mastermind]

Of course

 

[drf256]

Another thought on the subject,

Anyone here think that the factory opens assymetrically for ease on the rings sliding across them and not for performance???

 

[Mastermind]

Another thought on the subject,

Anyone here think that the factory opens assymetrically for ease on the rings sliding across them and not for performance???

I don't think so.

I could be wrong though.

 

[drf256]

Does the bottom ring ever reach the lower lip of the upper transfer in the engines where we raise the tops?

 

[Mastermind]

You mean in the transfer window?

 

[drf256]

Yes

 

[Mastermind]

On some saws I raise the roof of the lowers. In other words, I make the area between the lower and upper smaller. Not on the two port Stihls though.

 

[drf256]

On some saws I raise the roof of the lowers. In other words, I make the area between the lower and upper smaller. Not on the two port Stihls though.

May I ask why?

 

[Mastermind]

Why not on the Stihls?

If that's the question, they are never overly wide in my opinion.

Check out the 395XP



Then after some tweaking.

 

[Moparmyway]

Why not on the Stihls?

The more you take away from the lowers, the more case volume you add, which lowers velocity.
The stihls dont like less velocity

 

[Mastermind]

That seems to be true.

 

[Deets066]

That seems to be true.

It don't bother the huskies?

 

[Mastermind]

There's really no pat answers. I wish there were........

As a general rule though, the more open case volume, and wide transfer tunnels in the Stihl two port engines are lazy flowing. That's why we get away with taking the uppers so high. The smaller case volume, and tighter four port transfer tunnels in the Huskys allow more to be opened in the lowers, but they seem to get peaky if the uppers are too high.

There will be exceptions to every rule though, so don't take my thoughts as anything other than what I've seen in the saws I've tested.

 

[Deets066]

I've never been in a husky yet, but am planning to acquire a 394. Stratton said he'd share the numbers he's using in his (which looks awfully beastly) but I'm sure there are more tricks and techniques than just a set of numbers

 

[Mastermind]

I'll share all I have on em too. Hopefully you can do a thread on it and we can all learn some stuff.

 

[junkman]

Repped ^^^^^^^^^^^

 

[Deets066]

I will definitely do a thread when I get one, I've only ran two hooskies before. A 395 and a 350, wasn't impressed by either but in defense of the 395 it was sickly

 

[mdavlee]

You get a good 394/395 the 066s will be scared.

 

[Deets066]

Ok enough hijacking of Als thread,

I believe I'll keep my transfer timing straight across for the time being until I see any proof the slope actually helps