242/242xp piston question

[excess650]

I know that at least a few of you have already replaced pistons in your 242xps. I tried searching, but didn't uncover any photos, so the question is did your replacement piston have windows? Was it OEM or what aftermarket brand?

I revived a 242, and the piston in it, I'm assuming OEM, had windows. The replacement Meteor that I have does not despite being labeled 242/242xp. After making sure the saw was going to run OK with the cleaned cylinder and piston, I thought it might be a good idea to replace the piston and reduce the squish. Now I'm still wanting to close the squish, but am wondering which piston is going to give better results.

 

[excess650]

bump!

 

[blsnelling]

I'm watching to see what you find out as well. I have not done anything with mine yet.

 

[HiOctane]

Your cylinder should have closed ports.So with closed ports,you need window piston to let the fuel go from case to cyl.Unless the Meteor piston has non-full skirt(with "cutout" each side).But with a non full skirt and closed port cyl,performance will drop for sure.

 

[blsnelling]

I finally tore into my 242XPs today. I have three P&Cs. Two are Mahle sets, the other aftermarket. All look identical with windowed pistons. I've got one pretty much done. Max RPMs is 15K but too lean to get there. I haven't yet established a safe tune RPM, but will likely be around 14,500, maybe a little less. Compression is 175 hot!

 

[Jacob J.]

Your cylinder should have closed ports.So with closed ports,you need window piston to let the fuel go from case to cyl.Unless the Meteor piston has non-full skirt(with "cutout" each side).But with a non full skirt and closed port cyl,performance will drop for sure.

Yep- The 242 is a miniature 272 so the piston should look similar.

 

[blsnelling]

Turns out I've got 190 PSI cold. I pulled the rope out of the recoil testing it

 

[excess650]

My 242 was 160# but the squish can be reduced .015"-.020". I'm debating whether it will be worthwhile to mod the Meteor piston and install or not. The saw runs fine as is, but I was hoping for more revs. If I'm correct the muffler is just and empty can, so shouldn't be restrictive, but mine is awfully quiet.