boysen ports

[Arnold]

OK here it is, I just drilled some boysen ports in a test cylinder and would like some feed back from everyone. Keep in mind I don't have a way to build up the weld on the outside so I don't want to run the risk of blowing thru the outside wall. Any tips will be considered and appreciated. Thanks in advance.
Mobile Photobucket
Mobile Photobucket
Mobile Photobucket

 

[Wifesblaster]

Pics are kinda hard to see. When you are on photobucket copy the image link and paste it.

 

[Arnold]

 

[Blaaster]

Pic no work, in Photobucket just click on the image bar on the lower right of the screen and it is automatically copied to your clipboard.

Paste and your input should look something like this.

For obvious reasons my link is dead.

 

[Arnold]

Thanks for the tip blaaster but for some reason I cant get the img code on my phone. Does anyone know why when I upload new photos to bf they wont work at all? Check out some of the photos in my "my rebuild" album. None of the pics work and idk who to contact about this problem.

 

[Awk08]

i have the PB app.
upload pic, go into albums and find it, click to fully open it.
click menu on your phones bottom toolbar, choose show links, click on the .IMG link for forums, it auto copies the link, then paste into your post here.

forget the upload system on here.
it's not going to work until we're fully transfered to the new forum layout/server

 

[Arnold]

 

[Arnold]

 

[Arnold]

i have the PB app.
upload pic, go into albums and find it, click to fully open it.
click menu on your phones bottom toolbar, choose show links, click on the .IMG link for forums, it auto copies the link, then paste into your post here.

forget the upload system on here.
it's not going to work until we're fully transfered to the new forum layout/server

Thanks awk for the how too

 

[Arnold]

Any input on this?

 

[jbuckster07]

What is the purpose of this?? Never seen it before.

 

[Blaaster]

Boyesen ports, commonly known as boost ports, are to allow a little extra fuel/air charge to be supplied to the transfer ducts.

Basic 2 stroke Tuning

Short exert for you to read.
1) Starting with the piston at top dead center (TDC 0 degrees) ignition has occurred and the gasses in the combustion chamber are expanding and pushing down the piston. This pressurizes the crankcase causing the reed valve to close. At about 90 degrees after TDC the exhaust port opens ending the power stroke. A pressure wave of hot expanding gasses flows down the exhaust pipe. The blow-down phase has started and will end when the transfer ports open. The pressure in the cylinder must blow-down to below the pressure in the crankcase in order for the unburned mixture gasses to flow out the transfer ports during the scavenging phase.

2) Now the transfer ports are uncovered at about 120 degrees after TDC. The scavenging phase has begun. Meaning that the unburned mixture gasses are flowing out of the transfers and merging together to form a loop. The gasses travel up the back side of the cylinder and loops around in the cylinder head to scavenge out the burnt mixture gasses from the previous power stroke. It is critical that the burnt gasses are scavenged from the combustion chamber, in order to make room for as much unburned gasses as possible. That is the key to making more power in a two-stroke engine. The more unburned gasses you can squeeze into the combustion chamber, the more the engine will produce. Now the loop of unburned mixture gasses have traveled into the exhaust pipe's header section. The gasses aren't lost because a compression pressure wave has reflected from the end of the exhaust pipe, to pack the unburned gasses back into the cylinder before the piston closes off the port. This is the unique super-charging effect of two-stroke engines. The main advantage of two-stroke engines is that they can combust more volume of fuel/air mixture than the swept volume of the engine. Example: A 125cc four-stroke engine combusts about 110cc of F/A gasses but a 125cc two-stroke engine combusts about 180cc of F/A gasses.

3) Now the crankshaft has rotated past bottom dead center (BDC 180 degrees) and the piston is on the upstroke. The compression wave reflected from the exhaust pipe is packing the unburned gasses back in through the exhaust port as the piston closes off the port the start the compression phase. In the crankcase the pressure is below atmospheric producing a vacuum and a fresh charge of unburned mixture gasses is flowing through the reed valve into the crankcase.

4) The unburned mixture gasses are compresses and just before the piston reaches TDC, the ignition system discharges a spark causing the gasses to ignite and start the process all over again.

 

[Arnold]

So any input on the ports that I drilled? How is the location n should I reshape them in anyway or open them up some on the intake side?

 

[mud runner]

bumppppppppppppppp

 

[mud runner]

I think they should be a lil lower like maby here

 

[Blaaster]

I was about to add the above, most drillings I have seen have been in the lower area.

 

[Arnold]

OK what about the shape of them?

 

[mud runner]

most of the ones iv seen are round

 

[Arnold]

OK man I'll get these drilled for u and sent out on Monday

 

[mud runner]

OK man I'll get these drilled for u and sent out on Monday

ok sounds good 15151515