Another Porting Question

[big t double]

 

[Chris-PA]

I'm interested to see how that runs! Other than the easy start I bet it holds up fine.

On my Jenn Feng/McCulloch GZ4000 clone the compression ended up too high for the easy start system and I had to redesign it to defeat that. I'm sure that compression was less than what you have.

 

[Moparmyway]

Why not sand a little more away from the pop-up while you are doing the port work ?
Might put you closer to your targeted compression.

.008 is fine - just use a good oil mix of 32:1 ............. you are going to turn more rpm's

 

[drf255]

Nah.

Me Likey Compression. Gonna be a little screamer if my ports don't chew the rings up.

Gonna put a tach on it after breakin.

 

[lwhaples]

Interesting,glad I found your build.Will enjoy the vid.

 

[gritz]

I'm interested to see the outcome. Pretty cool idea. It should hold RPMs in the cut, but rev slower with a heavier piston, right?

 

[drf255]

I'm interested to see the outcome. Pretty cool idea. It should hold RPMs in the cut, but rev slower with a heavier piston, right?

Piston isn't heavier. Perhaps it's heavier than stock, but I couldn't measure that because it replaced a smaller ms230 piston.

I removed some metal under the dome. The piston came in 1.2 grams heavier than when I started. The stock ms250 pin and circlips actually weighed 1.2 grams less than the aftermarket. So all together I was at the same weight as when I started.

I'm assuming it's actually lighter than stock as the stocker is much more durable looking and heavier cast around the pin.

 

[drf255]

The end of this build was posted in this thread.

http://www.arboristsite.com/community/threads/ms250-too-much-compression.269144/

I had the bring the dome down.