Re: Oil Ratio: 1978 PA50

#CrazyWayne™ rocks. #CrazyWayne /
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The pipe changes all the pressures even in the combustion chamber.

Two Strokes basically have so many variables within them that you basically have to learn to work with what's going on it's not something that can be 100% calculated.

And things burn at different speeds at different pressures.

So the timing must be set to work with those pressures in order to get the efficiency.

The squash band will affect thermal transfer and burn flame front pattern.

Timing must match that.

Too much pressure and or Advance timing and you get death rattle maybe even hard sizes or get a hole in the top of your piston.

The heat range and design of the spark plug need to be of a different range or you can get pre ignition and or damage your piston.

And the exhaust chamber does more than just push a charge back into the cylinder.

You must think of a two-stroke is being somewhat like a cow with multiple stomachs.

A basic 4-stroke has a carburation or fuel injection a runner to the intake valve and things are drawn into the cylinder directly when the valve is open and the Piston is heading down .

A two-stroke draws from a carburetor much as a 4-stroke atomizing and mixing the fuel with air.

But it just drawn through possibly reads which create a turbulence which mix air and fuel more.

Now you have the hot crankcase and crankshaft spinning this breaks the fuel and air molecules down even more with the mixing process and the changing pressures that bring it from liquid to vapor.

Next you have the transfer ports and boost ports that are creating more turbulence stirring an rolling around mixing the fuel and air even further.

And the expansion chamber is now at a high vacuum which draws part of or most of the fuel air mix into the hot header pipe under great vacuum.

This high temperature in a vacuum causes the fuel and air to mix even further.

This vacuum will also put the crankcase into a state of vacuum.

It will even cause the Reeds to open and for even more air fuel mixture to enter the crankcase combustion chamber and Header.

The fresh air fuel mix coming through the Reeds and carburetor and this situation is cooler so it will be more dense.

Now the sonic wave within the pipe which is heated and moving faster than the speed of sound is now pushing and compressing.

So the hot compressed fule air mixture is now being stuffed back into the exhaust Port opening.

If everything's working correctly the transfer ports will just be closing as the wave begins to enter.

This pressure wave can reach pressures up to 25+ psi in the combustion chamber before the exhaust Port closes.

Combustion chamber size at top dead center must be large enough so that these pressures are not so high that you get dieseling or better known as death rattle without even a spark needed when this is happening.

You want to have it close to the edge of self-destruction.

In order to control this the timing is retarded.

The timing is not just retarded due to the fact that the compression is much higher.

It's also due to the fact that the air-fuel mixture has been mixed greatly to varying pressures orifices and then heated to even break it down to even a finer mix.

I'm sure if you check with your colleagues they will tell you that a fuel broken down to molecules and mixed more evenly with the oxygen and other elements in the atmosphere that you will have a much faster burn.

Another thing you need to have happen with a two stroke.

Is you need to feed heat into the expansion chamber/supercharger.

It is basically a Pulse Jet turn backwards.

And a pulse wave who's faster and works better with hotter and higher pressure gases.

The higher pressures and temperatures will give a better pumping cycle from the exhaust chamber.

To achieve this we need to have the fuel mix on the edge of still burning.

This is usually done by two things.

The number of degrees or distance the Piston must travel before the exhaust opens.

And a slight delay of the timing so you can get a little flick of Fire out the exhaust port.

Better known as feeding or putting the heat in the pipe.

And yeah you probably all heard this before but timing before jetting.

If your timing's not close your jetting fuel mix never will be.

And yes I do know that almost all of the piston downward pressure for power happens within the first 18 to 25 degrees after top dead center.

We also need to make sure that our timing is set to such that we don't get so much heat soak into the cylinder head piston and cylinder.

Peak power on a air-cooled 2-stroke happens at a much higher head temperature 385 to 460 Fahrenheit. The Sweet Spot temperature can vary depending on the cylinder and head design some small cooling fin heads will actually be at a higher temperature.

Such as pug's Moby's PA 50s NU50s....

Most of the air-cooled go-karts get Peak Power happens at about 418 degrees.

This is why I like the temperature of 420.

It's pretty much the temperature for Peak power on air-cooled setups with good cooling fins.

Most people notice heat fade/loss of power at temperatures exceeding 445 degrees.

This is usually caused by part of the fuel mix being burned at the edge of the exhaust port or in the header tube and returning as an inert gas.

The fuel is vaporizing so fast it just gets pushed into the exhaust and does not make it into the compression stroke.

It can even cause stalling or slowing of transfer flow into the combustion chamber.

A water-cooled setup can run usually 2 to 4 degrees more timing.

This is due to the fact that they can hold temperatures lower when the Piston is in the compression stroke this will slow down the burn speed of the mix.

So water cooled also has the advantage being able to run a higher compression ratio.

And I totally understand what you're talking about trying to go super fucking lean where you have no power are the engines just fails to have power or run.

But it will rev up beautifully on the kickstand.

You make it sound like I'm taking a drop of gasoline putting it on the floor in a basketball stadium igniting it and expecting the whole building to burst into flames, it won't happen.

And the same goes for a 20 gallon container of gas with a small air bubble if you light it it won't do much it's too rich.

The being too lean and too rich I'm referring to is basically being on the edge of the razor blade of the perfect tune.

Even Bell & Graham and many others out there over the years can tell you there's really no way to tell what's going to happen with all these two stroke variables you just gotten know what changes what and go with what this setup needs.

After doing it for a long time you get a good feel and knowledge of what works so i know what to start out with.

Basically everything from the air filter air box to the tip of the Stinger all have to be working together if you want to get the best power and or efficiency but whatever.

So go ahead and play with your fucking slide ruler all that other bullshit yes I understand what it's about.

But when you have this many variables happening it's just too many things changing too many other things to be able to stick the information into a fucking computer and get an answer.

So blather on say whatever bulshit you want to impress the computer geeks and millennials.

Basically you're just blowing smoke up my ass and I'm fluctuating it right back in your face with some splatter.

C.W.

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Subject Written By Posted
  Oil Ratio: 1978 PA50Topic by: Dean Shearsmith Dean Shearsmith 10/22/17 12:12PM
  Re: Oil Ratio: 1978 PA50Re: Don Sumpter (OFMC) Don Sumpter (OFMC) 10/22/17 12:59PM
  Re: Oil Ratio: 1978 PA50Re: Ryan . Ryan . 10/22/17 02:17PM
  Re: Oil Ratio: 1978 PA50Re: Lolita ✌ Lolita ✌ 10/28/17 06:56PM
  Re: Oil Ratio: 1978 PA50Re: frank dadog frank dadog 10/28/17 07:18PM
  Re: Oil Ratio: 1978 PA50Re: Lolita ✌ Lolita ✌ 10/28/17 07:27PM
  Re: Oil Ratio: 1978 PA50Re: Lolita ✌ Lolita ✌ 10/28/17 07:34PM
  Re: Oil Ratio: 1978 PA50Re: frank dadog frank dadog 10/28/17 08:20PM
  Re: Oil Ratio: 1978 PA50Re: Lolita ✌ Lolita ✌ 10/29/17 11:33AM
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  Re: Oil Ratio: 1978 PA50Re: Lolita ✌ Lolita ✌ 10/29/17 02:55PM
  Re: Oil Ratio: 1978 PA50Re: Charles Cole (OFMC) Charles Cole (OFMC) 10/29/17 10:20AM
  Re: Oil Ratio: 1978 PA50Re: #CrazyWayne™ rocks. #CrazyWayne #CrazyWayne™ rocks. #CrazyWayne 10/29/17 12:02PM
  Re: Oil Ratio: 1978 PA50Re: Lolita ✌ Lolita ✌ 10/29/17 12:26PM
  Re: Oil Ratio: 1978 PA50Re: #CrazyWayne™ rocks. #CrazyWayne #CrazyWayne™ rocks. #CrazyWayne 10/29/17 01:32PM
  Re: Oil Ratio: 1978 PA50Re: Lolita ✌ Lolita ✌ 10/29/17 02:56PM
  Re: Oil Ratio: 1978 PA50Re: #CrazyWayne™ rocks. #CrazyWayne #CrazyWayne™ rocks. #CrazyWayne 10/29/17 03:39PM
  Re: Oil Ratio: 1978 PA50Re: Lolita ✌ Lolita ✌ 10/29/17 04:07PM
  Re: Oil Ratio: 1978 PA50Re: frank dadog frank dadog 10/29/17 03:51PM
  Re: Oil Ratio: 1978 PA50Re: Charlie BUZZARD Charlie BUZZARD 10/29/17 12:39PM
  Re: Oil Ratio: 1978 PA50Re: Lolita ✌ Lolita ✌ 10/29/17 01:00PM
  Re: Oil Ratio: 1978 PA50Re: Charlie BUZZARD Charlie BUZZARD 10/29/17 08:28PM
  Re: Oil Ratio: 1978 PA50Re: Lolita ✌ Lolita ✌ 10/30/17 12:20AM
  Re: Oil Ratio: 1978 PA50Re: frank dadog frank dadog 10/30/17 03:24PM
  Re: Oil Ratio: 1978 PA50Re: #CrazyWayne™ rocks. #CrazyWayne #CrazyWayne™ rocks. #CrazyWayne 10/30/17 10:00PM
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  Re: Oil Ratio: 1978 PA50Re: #CrazyWayne™ rocks. #CrazyWayne #CrazyWayne™ rocks. #CrazyWayne 10/30/17 10:40PM
  Re: Oil Ratio: 1978 PA50Re: frank dadog frank dadog 10/30/17 10:45PM
  Re: Oil Ratio: 1978 PA50Re: Ryan . Ryan . 10/29/17 01:02PM
  Re: Oil Ratio: 1978 PA50Re: frank dadog frank dadog 10/30/17 10:41PM
  Re: Oil Ratio: 1978 PA50Re: #CrazyWayne™ rocks. #CrazyWayne #CrazyWayne™ rocks. #CrazyWayne 10/31/17 12:36AM
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  Re: Oil Ratio: 1978 PA50Re: frank dadog frank dadog 10/31/17 10:09AM
  Re: Oil Ratio: 1978 PA50Re: jayson sumpter jayson sumpter 10/31/17 10:21AM
  Re: Oil Ratio: 1978 PA50Re: #CrazyWayne™ rocks. #CrazyWayne #CrazyWayne™ rocks. #CrazyWayne 10/31/17 03:38PM
  Re: Oil Ratio: 1978 PA50Re: frank dadog frank dadog 10/31/17 04:58PM
  Re: Oil Ratio: 1978 PA50Re: jayson sumpter jayson sumpter 10/31/17 05:00PM
  Re: Oil Ratio: 1978 PA50Re: frank dadog frank dadog 10/31/17 10:18AM
  Re: Oil Ratio: 1978 PA50Re: Lolita ✌ Lolita ✌ 10/31/17 11:59AM
  Re: Oil Ratio: 1978 PA50Re: Stephen Keller Stephen Keller 10/31/17 02:34PM
  Re: Oil Ratio: 1978 PA50Re: Mark Booth Mark Booth 10/31/17 04:06PM
  Re: Oil Ratio: 1978 PA50Re: #CrazyWayne™ rocks. #CrazyWayne #CrazyWayne™ rocks. #CrazyWayne 11/01/17 02:36AM
  Re: Oil Ratio: 1978 PA50Re: Dean Shearsmith Dean Shearsmith 10/31/17 07:40PM
  Re: Oil Ratio: 1978 PA50Re: Charlie BUZZARD Charlie BUZZARD 10/31/17 04:31PM
  Re: Oil Ratio: 1978 PA50Re: frank dadog frank dadog 10/31/17 08:35PM
  Re: Oil Ratio: 1978 PA50Re: #CrazyWayne™ rocks. #CrazyWayne #CrazyWayne™ rocks. #CrazyWayne 11/01/17 09:45AM
  Re: Oil Ratio: 1978 PA50Re: frank dadog frank dadog 11/01/17 10:50AM
  Re: Oil Ratio: 1978 PA50Re: #CrazyWayne™ rocks. #CrazyWayne #CrazyWayne™ rocks. #CrazyWayne 11/01/17 12:14PM
  Re: Oil Ratio: 1978 PA50Re: Charlie BUZZARD Charlie BUZZARD 11/01/17 12:20PM
  Re: Oil Ratio: 1978 PA50Re: frank dadog frank dadog 11/01/17 01:20PM
  Re: Oil Ratio: 1978 PA50Re: #CrazyWayne™ rocks. #CrazyWayne #CrazyWayne™ rocks. #CrazyWayne 11/01/17 03:18PM
  Re: Oil Ratio: 1978 PA50Re: frank dadog frank dadog 11/01/17 04:32PM
  Re: Oil Ratio: 1978 PA50Re: #CrazyWayne™ rocks. #CrazyWayne #CrazyWayne™ rocks. #CrazyWayne 11/01/17 08:18PM
  Re: Oil Ratio: 1978 PA50Re: frank dadog frank dadog 11/01/17 08:53PM
  Re: Oil Ratio: 1978 PA50Re: frank dadog frank dadog 11/01/17 09:20PM
  Re: Oil Ratio: 1978 PA50Re: Lolita ✌ Lolita ✌ 11/01/17 09:26PM
  Re: Oil Ratio: 1978 PA50Re: #CrazyWayne™ rocks. #CrazyWayne #CrazyWayne™ rocks. #CrazyWayne 11/01/17 09:34PM
  Re: Oil Ratio: 1978 PA50Re: frank dadog frank dadog 11/01/17 09:52PM
  Re: Oil Ratio: 1978 PA50Re: Lolita ✌ Lolita ✌ 11/01/17 10:19PM
  Re: Oil Ratio: 1978 PA50Re: frank dadog frank dadog 11/01/17 11:57AM
  Re: Oil Ratio: 1978 PA50Re: frank dadog frank dadog 11/01/17 02:40PM
  Re: Oil Ratio: 1978 PA50Re: Lolita ✌ Lolita ✌ 11/01/17 02:53PM
  Re: Oil Ratio: 1978 PA50Re: #CrazyWayne™ rocks. #CrazyWayne #CrazyWayne™ rocks. #CrazyWayne 11/01/17 03:21PM
  Re: Oil Ratio: 1978 PA50Re: frank dadog frank dadog 11/01/17 04:44PM
  Re: Oil Ratio: 1978 PA50Re: #CrazyWayne™ rocks. #CrazyWayne #CrazyWayne™ rocks. #CrazyWayne 11/01/17 08:24PM
  Re: Oil Ratio: 1978 PA50Re: Lolita ✌ Lolita ✌ 11/01/17 09:04PM
  Re: Oil Ratio: 1978 PA50Re: frank dadog frank dadog 11/01/17 09:07PM
  Re: Oil Ratio: 1978 PA50Re: Lolita ✌ Lolita ✌ 11/01/17 09:13PM
  Re: Oil Ratio: 1978 PA50Re: frank dadog frank dadog 11/01/17 10:37PM
  Re: Oil Ratio: 1978 PA50Re: #CrazyWayne™ rocks. #CrazyWayne #CrazyWayne™ rocks. #CrazyWayne 11/01/17 11:09PM
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  Re: Oil Ratio: 1978 PA50Re: #CrazyWayne™ rocks. #CrazyWayne #CrazyWayne™ rocks. #CrazyWayne 11/02/17 09:28AM
  Re: Oil Ratio: 1978 PA50Re: jayson sumpter jayson sumpter 11/02/17 09:30AM
  Re: Oil Ratio: 1978 PA50Re: frank dadog frank dadog 11/02/17 10:00AM
  Re: Oil Ratio: 1978 PA50Re: #CrazyWayne™ rocks. #CrazyWayne #CrazyWayne™ rocks. #CrazyWayne 11/02/17 10:08AM

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