Main vs Aux transfers timing in Husky 372XP

[Frank Savage]

I have some noname 50mm topend to play with and I´m wondering about this:

To make the Aux transfers opening a wee bit before the mains. To get more uniform wash of the chamber with maybe less washout of the fresh mix. Maybe even with a realy slight sloping top, to open the utmost rear corner first.
I did a real torque monster before, with fingerports, capable of cutting through nails, wire ropes and fences in the wood with no indication in the sound or revs (only chain dulled and chipping pieces of teeth were flying off). But it had only a very narrow powerband, was a real gas guzzler and quite useless dog outside the optimal rev range. So quickly I went back to only slightly modded factory topend setup.
I don´t want to get the same result as with the fingerports. Preferably rise the power by some 10-12%, boost the mileage a bit and to get as little fresh mix washout as possible-for occasions when I work with the saw up in the tree, just in front of my nose.
The timing will be like In 80°, Ex 100°, Transfers around 120°, Blowdown 22-23°. Probably a slight shelf in the exhaust, shooting for like 0,015-0,018 squish.

Experiences, coments, ideas?

 

[blsnelling]

Exhaust 100° and transfers 120° is 20° of blowdown, not 22°-23°. Personally, I like 18°-20° on a 372 with the exhaust at 98°-100°. I like the intake 78°-80° max.

 

[Frank Savage]

You´re right sir, that comes from writing while doing something utterly else, no matter the "around 120°".
Well, I was of that opinion that longer blowdown has some benefits for torque and that torquey topend with BD of very close to 24° was a statisticaly insignificant proof-but the fact is, that scavenging was rather poor and limiting throttle response, until the fingerports were added (and then the revs went up, but at the vast expense of fuel mileage, comfort, throttle response from idle (overflowing problems), user comfort-needed carb adjustment twice during heating up...)
Suppose the shorter blowdown is good for revs and response, because of better and more controlable scavenging-probably better way to go on the 372, which is more of the snappy than torquey nature anyway...

 

[blsnelling]

There is no lack of torque with these numbers.

 

[blsnelling]

Of course, there's a lot more to it than just the numbers.

 

[Frank Savage]

I know... Well, realy no lack of torque there. Is that an oak?

I realy wonder about the aux timed a wee bit in advance to mains, if it helps anything...

 

[blsnelling]

If anything, I open the mains a couple degrees early.

 

[Frank Savage]

Did some refreshing and homework study, thanks for the kicker...
Until now I was much under influence from my past when dealing a bit with model aircraft engine with Perry (?) scavenging system, which has deflector on the piston. Flat piston is so utterly different beast, but albeit I "knew", the old biases were realy deeprooted.

To open properly set mains first makes waay more sense

 

[Frank Savage]

Finished some 2stroke reading, aux opened before mains was obviously infrequently, but used setup. Realy no experience in a saw?
Even like "been there, done that, but " would be kind of good ansver (joking aside, pls)