Porting MS261

[Grqnbech]

Hi

Im about to port My used Ms261, and I Will not be using the strato... I Will remove the divider

So I was thinking to do finger ports from the strato port up to the transfer ports... Is this a No go or would it work??

Thomas

 

[blsnelling]

No need but you can try it.

 

[blsnelling]

BTW it won't be a finger. There's only about a 1/16"-1/8" divider between the two.

 

[Grqnbech]

Thanks Brad you know what I Mean.... By the way, I am a big fan of your threads...
I Will let you know if it is worth the trouble

 

[blsnelling]

If it's MTronic you MUST leave the divider in the carb.

 

[blsnelling]

Level your transfers but do not raise them higher than the highest point.

 

[Grqnbech]

It is not Mtronic... Ok but make transfers wider towards intake right?

Do you run yours with only one piston ring?

Thanks for your input

 

[blsnelling]

I make the transfers and strato ports the same width, no wider. Watch your ring ends!

 

[Grqnbech]

Just thinking out loud here... If I did a fingerport from the strato port to the transfer port, then when the piston opens the transfer ports, the air/fuel mix Will be pulled both from the carb, and the crankcase.... Will this not be a problem?

 

[drf255]

A finger port is a port that’s ground through the plating into the cylinder wall that goes from the positive pressure lower and ends blindly in the cylinder wall. It’s a poor man’s extra port generally used to increase transfer area in a dual port 2 stroke engine.

You are referring to a “bridge” port. That’s one that goes between one port and another in the plating.

I personally wouldn’t do what you are suggesting. There’s a lot of fineness in those ports and that slug. Much of your intake timing comes from the transfers pulling fresh air in through the uppers via the strato. You are risking blowing charge back into the stratos by doing what you are saying.

I vote No.

 

[Grqnbech]

A finger port is a port that’s ground through the plating into the cylinder wall that goes from the positive pressure lower and ends blindly in the cylinder wall. It’s a poor man’s extra port generally used to increase transfer area in a dual port 2 stroke engine.

You are referring to a “bridge” port. That’s one that goes between one port and another in the plating.

I personally wouldn’t do what you are suggesting. There’s a lot of fineness in those ports and that slug. Much of your intake timing comes from the transfers pulling fresh air in through the uppers via the strato. You are risking blowing charge back into the stratos by doing what you are saying.

I vote No.

Thanks... That's what I thought. Risk of blow back

Thanks of your reply

 

[Grqnbech]

So here is a little update...

 

[Swedenchainsaws]

Did it make i difference when you removed all that? I have 261, without m-tronic. ANd i have been raising exhaust, and lowered intake i tiny little bit. And the saw runs good, but its not near as snappy as my Husky 550...