026 MS260 questions.

[MaddBomber]

My '08 MS260 has lost compression and the top end is spanked. Carbon scored badly and piston is cracked....but she still runs! Lol.
Anyway, I have an 026 that seems to have low hours, but the case is corroded very badly. Cement floor syndrome , is my guess.
The MS260 is the 44.7mm bore and the 026 is 44mm... though, despite using 3 different micrometers, it's measuring at 43.79mm...so I'm guessing it's 44mm.
Is there a "feelable" power gain with the 44.7mm or should I just swap them and not look back.
Both are "Pro" models, both are Mahle.... which is why I hesitate to order a new P&C. Last time, my dealer gave me NWP stuff, but that was for a 371xp/2071....I'm not knocking NWP, as the bearings and P&C are still going strong at almost 150 tanks....though she's a shelf queen because the MS462c is just phenomenal.
The little MS260 is well over 250 tanks.... for reference.

 

[SteveSr]

Just put the 026 top end on the MS260. Although I have never done it I believe it is a drop-in replacement. The extra displacement was mainly to compensate for power losses caused by EPA muffler restrictions.

 

[dmb2613]

Check for leaks vacum and pressure, seals may be bad as well ae the rubber parts, Then you will have a good as new saw

 

[MaddBomber]

Excellent. Thanks.
I fully intend on pressure/vac testing it. 12 year old rubber with hundreds of warming cycles, isn't exactly ideal.

 

[drf255]

Add the 44mm cylinder. Open the muffler a bit. Saw should have more and not less power. The older 026 cylinders had better port timing too (in many cases).