Husky 570 Crank Stuffers. Keep or Ditch?

[Barn Shop]

The idea behind the stuffers is that more case vacuum is built when the piston is on its way up and more pressure is built on the way down before the transfers open. The results are a higher but narrower rpm hp range

The idea behind the stuffers is that more case vacuum is built when the piston is on its way up and more pressure is built on the way down before the transfers open. The results are a higher but narrower rpm hp range

I understand what your saying but I'm not buying it, Amount of Vacuum Drawn is a result of piston size and stroke, small piston and stroke smaller draw, larger piston and stroke larger draw regardless of case volume. The amount of vacuum measured in inches of mercury hg is controlled by the inlet opening size and speed rpm to a point of the engine and again with the piston and stroke size having a controlling effect. I would buy into the idea if the crankcase was empty lack of a fuel charge but it isn't so in my wisdom of thinking if you have a larger area that is fully charged with mix you will build more pressure on the down stroke where the vacuum drawn will still be controlled by piston stroke and intake opening size.
But Hey what the Hell do I Know, I'm just an ole Redneck Hillbilly.

 

[Kiwioilboiler]

I understand what your saying but I'm not buying it, Amount of Vacuum Drawn is a result of piston size and stroke, small piston and stroke smaller draw, larger piston and stroke larger draw regardless of case volume. The amount of vacuum measured in inches of mercury hg is controlled by the inlet opening size and speed rpm to a point of the engine and again with the piston and stroke size having a controlling effect. I would buy into the idea if the crankcase was empty lack of a fuel charge but it isn't so in my wisdom of thinking if you have a larger area that is fully charged with mix you will build more pressure on the down stroke where the vacuum drawn will still be controlled by piston stroke and intake opening size.
But Hey what the Hell do I Know, I'm just an ole Redneck Hillbilly.

You do you. Me, I'll do @huskihl . So to speak.

 

[Duce]

I know there is a 570 for sale on local marketplace, looks clean.

 

[Bjorn]

Hello, almost every modern high performance 2-stroke engine. Have crankstuffers, reeds and expensionchamber for the exhaust. That is a great combination. That Can deliver much power. A 80cc chainsaw that is ported Can Maybee deliver 10 HP, But a 80cc dirtbike Will deliver 25-30 HP. Only because it is build with the right produkts, crankstuffers is one of the great stuff.

 

[Dolkitafreak]

Hello, almost every modern high performance 2-stroke engine. Have crankstuffers, reeds and expensionchamber for the exhaust. That is a great combination. That Can deliver much power. A 80cc chainsaw that is ported Can Maybee deliver 10 HP, But a 80cc dirtbike Will deliver 25-30 HP. Only because it is build with the right produkts, crankstuffers is one of the great stuff.

So much more to factor in there. Look at the stroke of those bikes versus a chainsaw…

 

[Bjorn]

Yes, dirtbikes have much more longer stroke. So there is a big differens.

 

[redneckhillbilly]

high volume vs high velocity, reminds me of the oldtimer hotroders in my family argueing about olds vs chevy big blocks

 

[Bjorn]

high volume vs high velocity, reminds me of the oldtimer hotroders in my family argueing about olds vs chevy big blocks

A Supercharger Will do both, velocity and volume.

 

[Bjorn]

Runs nice
Might be a while before it sees timber though, we are badly flooded here at the moment.

5 1/2 Months flood in Australia, must be a new world record.

 

[Bjorn]

Here is a perplexing problem with saw cranks, the counterweights I'm guessing are about 1/3 of a circle so lower crankcase compression ratio. But take the piston and cylinder off your saw and turn the crank to BDC so it's at the bottom of the downstroke- when the transfer ports are open... Now look at the crank,it's counterweights are at the top of the crankcase and a large part of your fuel/air charge(about 2/3 of the crankcase volume) is trapped in the bottom of the crankcase with the counterweights above blocking your fuel charge from getting up past them to the transfer ports,considering the short amount of time the transfers are open.