Building a Dome piston

Arborist Forum

Help Support Arborist Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
Husq445

Husq445

ArboristSite Operative
Joined
Aug 18, 2009
Messages
285
Location
Iowa
Just wondering if anyone has done this and what fill rod they used, this is with 4043.

Saw is running Awesome! My ring was shot when these compression readings were taken, new one on the way.

120 stock, worn ring
175 dome, worn ring
? , new ring

Anyway here are the pics of the piston.
They were not quite finished in the photos, but gives you a good idea.


Cant stop Modding my saw!
 
Ol' Brian

Ol' Brian

ArboristSite Guru
Joined
Jun 4, 2009
Messages
648
Location
Southwestern Illinois
How much effect do you think the extra weight in the piston will have on how much the saw vibrates? Did you weigh the piston before and after? Just curious.

Excellent work! How did you round off the dome? Did you chuck the piston up in a lathe?
 
MotorSeven

MotorSeven

Addicted to ArboristSite
Joined
Mar 23, 2006
Messages
1,374
Location
NE TN
How much effect do you think the extra weight in the piston will have on how much the saw vibrates? Did you weigh the piston before and after? Just curious.

Excellent work! How did you round off the dome? Did you chuck the piston up in a lathe?


X2..

and...

175 with a "worn ring"? with new rings will this thing even stay together?

:popcorn:
 
timberwolf

timberwolf

Addicted to ArboristSite
Joined
Aug 29, 2002
Messages
3,801
Location
Ontario
Looks good. At 2.8 grams a cc and by the looks of it about 2ccs that will make 5 or 6 grams difference to piston weight. Big bore pistons are easily that much mass and work without any noticable balance issues.

A 2 stroke single is only partially balanced so it's not all that critical.

I'd guess the compression will jump about 50 psi by the looks of it. (edit I see thats what it did) Cyl and piston were down 40 psi to start though so fix that up and its going to be well up over 200. might need to shave a little off the top if you want to work with the saw. Also an idea to watch how close the spark plug is to the pop up, get too close and it will turn into a hot spot on the piston.
 
Last edited:
nategyoder

nategyoder

ArboristSite Operative
Joined
Apr 28, 2009
Messages
146
Location
Elkhart IN
What are the advantages and disadvantages of popups vs. domed? The domed look like they would be more difficult to do is that why we see more popup style on here? Very cool work!
 
wigglesworth

wigglesworth

Booned
Joined
Oct 5, 2008
Messages
8,175
Location
West kentucky
Now thats what Im talkin about!!

attachment.php
 
Top