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Project Stumpbroke How I do it

Stumpys Customs

Stumpys Customs

Stumpbroke
Joined
Jan 16, 2010
Messages
5,203
Location
south central MO
Thought a few of ya's might want a lil more in depth look at how I port a saw. I'll be using my current project a Stihl MS460 to illustrate. Feel free to ask ?'s. I'll do my best to answer. I do want to add this is not the only way to do it, just the way I do it.

Just a run of the mill well used MS460 with a couple of new parts to go with it.


Normal grit & grime from being used for it's intended purpose.


The first step is to get everything as clean as possible. I have a parts washer outside the shack that the saws take a bath in.
 
jhutton

jhutton

ArboristSite Lurker
Joined
Jun 10, 2012
Messages
10
Location
va
Stump, you must have one hellva solution in the parts washer...that stuff cleans! mind sharing the mixing ratio and contents.Looks like gloves need to be worn with face shield.....Later Jody
 
Hedgerow

Hedgerow

HACK
Joined
Dec 20, 2010
Messages
15,356
Location
Carthage, MO
Stump, you must have one hellva solution in the parts washer...that stuff cleans! mind sharing the mixing ratio and contents.Looks like gloves need to be worn with face shield.....Later Jody

Yea... How much just to clean the saw??? I got this really nasty thing...
Well...:msp_sneaky:
 
Stumpys Customs

Stumpys Customs

Stumpbroke
Joined
Jan 16, 2010
Messages
5,203
Location
south central MO
Stump, you must have one hellva solution in the parts washer...that stuff cleans! mind sharing the mixing ratio and contents.Looks like gloves need to be worn with face shield.....Later Jody

It's just parts cleaner from the local hardware store. I think it's just mineral spirits. I just use a brush & some elbow grease to get em clean. I usually wear gloves, but sometimes I don't. It's not all that harsh.
 
Stumpys Customs

Stumpys Customs

Stumpbroke
Joined
Jan 16, 2010
Messages
5,203
Location
south central MO
After I get the machining done I install the piston & cyl and set up the degree wheel to start marking out how much I need to take off the ports to get them where I want. I start with the ex, then the upper transfers, and on to the intake. I turn the degree wheel to the number I want then I make a mark on the piston for the intake & exhaust thenmeasure from the edge to the line to give me the amount of material to remove from the port. on the transfers I have to make a mark at where the port is before grinding & then turn the wheel to the desired degree & make another mark. I hope that all makes sence.:msp_confused:

Here's the ex side of the piston with the marks. The top one is how much I need to remove from the roof of the ex port. The middle mark is the Upper transfer mark. It lined up with the top of the second ring groove when the top of the piston was even with the trans port.
The bottom mark is how much of the skirt is below the ex port @ TDC.


The intake side is done the same way as the ex. I set the wheel to the degree I want it at & make a mark on the skirt. The upper mark is just a reference to where top of the intake port is on the piston @ BDC.
 
Stumpys Customs

Stumpys Customs

Stumpbroke
Joined
Jan 16, 2010
Messages
5,203
Location
south central MO
Now I'm ready to lay the cyl out. Are the tools I use for that


Here's the intake side lay'd out. I use the piston as a straight edge for the horizontal marks & the little square for the vertical ones.


On the transfers I use the piston ring for a straight edge on the horizontal marks.




I also use the ring for the top of the ex port


the ex flange just gets a straight edge mark & I eyeball the radius's
 
Stumpys Customs

Stumpys Customs

Stumpbroke
Joined
Jan 16, 2010
Messages
5,203
Location
south central MO
For the next step I'll be using these tools, 1/4" die grinder with a 5/16" round nose bur, and a bit of oil to keep the bit lubed from time to time.


I start out on the outside of the ex port to open it up first.



Then I move to the inside of the port


I then move back to the outside to blend it all together. This is what the ex port looks like roughed out.


 
Last edited:
Stumpys Customs

Stumpys Customs

Stumpbroke
Joined
Jan 16, 2010
Messages
5,203
Location
south central MO
Thought I'd throw in a pick of my little vise with plastic jaw inserts.


Time to move onto the intake side. I start on it from the inside.


Then on to the outside


All roughed out with the same bur that I used on the ex.


I've learned from experience that you have to be careful with the clutch side on some of the stihls since the port is angled. You can go right through the side where I've got the arrow & line on the base of the boot flange. I've had to weld a couple of holes up before, but it's been a while since I've had to do that. Live & learn.
 
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