Chainsaw Repair

I got an 026 that was missing parts when I got it, I put a Tecomec piston (made in China not Italy) says so on the box, had to use cylinder base gasket, piston hit top. It had a 3/8 sproket and I only had a 20" bar 3/8 squire grind chain. It has open muffler, adjustable carb and it is the sickest saw I got. Is this par for the course? too much chain? maybe 3/8 LP would help? I never owned one of these is the reson I ask. I like Stihl but my 350 Husky will run all over it, .325 chain on it though.
Thanks,
DJ

16" 325 IMO  is what they is

Or better yet ....Stihl 63PS on a 16" Picco bar.
18"-20" in Cannon Super Mini NK bars

I like the 18 or 20 bar because of me bending over, my back is a mess and the longer bar helps some. I was only cutting pine maybe 10 or 12" at the most and smaller. It runs real good just not much power. I took the 20" off my 660 so I was leaning on it too hard. I never had or used an 026 and just expected too much I guess. I just wonder why it was set up for regular 3/8, it's a Stihl drum and rim.

I got some 18" .325 Stihl bars, think I got a 16" too so all I need is a .325 rim. Also got a small spline 7tooth 3/8 LP rim too just need a bar.

Thanks for the help,
DJ

Speaking of short bars. Last fall I set up my 550XP with a 13"  Homelite Windsor bar I made up by shortening from 15".
Ran Stihl 33 Topic Super 3/8 chisel on it. Best for limbing small spruce laying on the ground knee high. 550 with rev boost and 13" rips like crazy for production.😁
Here's some nice pics where I have to do residential removals. Just like a day off