Husqvarna 550xp pop up

[Terry Syd]

Why bother? The strato may furnish fresh air, but that (air) is what you need to make more power.

With the turbulence in the cylinder and especially at TDC with the squish the cylinder charge (air, exhaust, mixture) is essentially a homogeneous mixture - it is all mixed together.

That's why a 'strato' can work, the mixture is homogeneous when it starts to burn. (you may have noticed that the stratos are making more power than older designs)

If you mix the two flows you will simply be loosing mixture out the exhaust port during the cylinder charging phase. You still have the same air in the cylinder, but some of the fuel will go out the exhaust port. In other words, you will have increased the fuel consumption without an increase in power.

 

[tree monkey]

Why bother? The strato may furnish fresh air, but that (air) is what you need to make more power.

With the turbulence in the cylinder and especially at TDC with the squish the cylinder charge (air, exhaust, mixture) is essentially a homogeneous mixture - it is all mixed together.

That's why a 'strato' can work, the mixture is homogeneous when it starts to burn. (you may have noticed that the stratos are making more power than older designs)

If you mix the two flows you will simply be loosing mixture out the exhaust port during the cylinder charging phase. You still have the same air in the cylinder, but some of the fuel will go out the exhaust port. In other words, you will have increased the fuel consumption without an increase in power.

you tell em terry, I've tried for a couple years

also any fuel going through the strato's doesn't lube or cool the engine

 

[Farmchuck]

Ok good to know, I’d gladly trade a stock one back for it if it wasn’t being used. These dam auto saws are loud though with the muffler opened up, ear piercing loud! I wouldn’t think to run them without hearing protection

Glad to hear I’m not the only one who can’t take the racket.

 

[mortalitool]

 

[Chainsaw Jim]

You still have the same air in the cylinder, but some of the fuel will go out the exhaust port. In other words, you will have increased the fuel consumption without an increase in power.

Every time I read this it makes me wonder if an expansion chamber pipe has been used to pack that fuel back in the chamber, and what kind of increase in power it can make.

 

[tree monkey]

those pipes kinda get in the way in the woods, do they work on a work saw? yep been there did that.

 

[usmcbuckwild]

those pipes kinda get in the way in the woods, do they work on a work saw? yep been there did that.

To remedy that could you make the pipe to run under the saw, squared off on the bottom so you can set it down and it won’t fall over? More rectangular than round? Take up less space and be more user friendly?

 

[WKEND LUMBERJAK]

To remedy that could you make the pipe to run under the saw, squared off on the bottom so you can set it down and it won’t fall over? More rectangular than round? Take up less space and be more user friendly?

Sounds like a good build thread for some one.

 

[usmcbuckwild]

Sounds like a good build thread for some one.

I would follow that thread

 

[WKEND LUMBERJAK]

I would follow that thread

Me to when are you starting it.

 

[tree monkey]

 

[usmcbuckwild]

Me to when are you starting it.

If I knew how, there would already be a thread

 

[Terry Syd]

Scott, I see from your grey beard you have aged a bit from when your avatar was taken...

 

[WoodsliverDan]

Ok ladies, got a bar on the 550xp today and had a chance to run it with @Red97 in a sugar maple log. I used a 20" 3/8 bar and it ran phenomenal, even at full cut. I had a chance to run both of Joe's echos, the 730 hybrid and the 8000 he just worked up. Both ran great! I especially loved the hybrid due to the weight and the power output. Now to get started on a stock 550 vs my worked up one..

 

[Red97]

Short clip in smaller wood, ran well with the bar buried too. Forgot how snappy these 550s are.

Might make me go into my 261c....

 

[WoodsliverDan]

Oh! Joe also showed me his jug today, interesting stuff!

 

[AlfA01]

Short clip in smaller wood, ran well with the bar buried too. Forgot how snappy these 550s are.

Might make me go into my 261c....

That Dolmar blade improved cut time by 10% at least...

 

[Tor R]

Most of the modern pro/semi pro Huskies has crankcases for multiple setup, things like heathed system or Trio brake system.
While a G setup doesnt mather since it's just two holes underneath the flywheel, the setup for the Trio Brake do mather a bit when we're speaking about as good cooling as possible.

The Trio Brake system looks like this (this is an 346):




I doubt they sell more then ruffly 5% 550 Trio Brake saws, but all their crankcases has the mounting ears for the brake system, this is how I choose to prepare a 550 case for a build up (Husqvarna has done the same when they upgraded their 560 crankcase):

 

[Farmchuck]

Most of the modern pro/semi pro Huskies has crankcases for multiple setup, things like heathed system or Trio brake system.
While a G setup doesnt mather since it's just two holes underneath the flywheel, the setup for the Trio Brake do mather a bit when we're speaking about as good cooling as possible.

The Trio Brake system looks like this (this is an 346):
View attachment 155621

View attachment 155622

I doubt they sell more then ruffly 5% 550 Trio Brake saws, but all their crankcases has the mounting ears for the brake system, this is how I choose to prepare a 550 case for a build up (Husqvarna has done the same when they upgraded their 560 crankcase):

View attachment 155619

View attachment 155620

When you do a build up on a 550 what kind of modification do you do to the muffler?

 

[WoodsliverDan]

Most of the modern pro/semi pro Huskies has crankcases for multiple setup, things like heathed system or Trio brake system.
While a G setup doesnt mather since it's just two holes underneath the flywheel, the setup for the Trio Brake do mather a bit when we're speaking about as good cooling as possible.

The Trio Brake system looks like this (this is an 346):
View attachment 155621

View attachment 155622

I doubt they sell more then ruffly 5% 550 Trio Brake saws, but all their crankcases has the mounting ears for the brake system, this is how I choose to prepare a 550 case for a build up (Husqvarna has done the same when they upgraded their 560 crankcase):

View attachment 155619

View attachment 155620

I should have cut those ears off on mine when I was working on it. What a pain in the @ss to get the wrist pin out with that thing there!