Chainsaw Repair

Air filter cover has 97 inside.

Gil2 cylinder was closed.

Now I swear in Walts video they showed a open 50mm 670 cylinder too. Were all closed on 670 or was there both?

outer spike  503590701

carb HS230D

outer bar plate 501444501

base gasket 501512204

piston 501659403

stud 503 20 82-04   503208204

I have never seen an open port for a 670.

Ya we were talking about that yesterday. Were thinking they had the later 50mm 268 open port in video.
Would have to watch again to tell or what he said.

Talking with a guy in CRB that collects and from his reading on them.    = between the Mahle , KS, Gil2, the Gil was the hottest running they said

I didnt know they used KS on them too.



Jhmn = The mahle is probably the most generic of the bunch. It has a combustion chamber like the 268 and average sized ports.

The KS has a combustion chamber like the mahle but had larger lower transfers and a step on the bottom of the exhaust port.

The gilardoni has a smaller combustion chamber large lower transfers and the step in the exhaust port as well.

Gilardoni, is definitely the hottest running of the 3 in stock form.
     
     mahle cylinders have had mahle pistons and my ks and gilardoni have had ks pistons.
     





SS = On the 67cc cylinders...
The 66 is an open port average cylinder.
The 266 is closed port Mahle, small Double D combustion chamber with smaller than average ports, very high compression.
The 268 is a open port made by Gillardoni and very well made at that, make lots of torque.
The 268XP is a closed port usually a Mahle with a large circular combustion chamber and average size ports.
The 670 is a closed port (KS?) and has a large circular combustion chamber with the largest ports of all them.

The 66 is like the 61's bigger brother and like the 61 a very solid saw.
The 268 and 268XP are the easiest and best of this bunch to get parts for and keep running.
The 266 is the lil hot rod of the group and the most different, and as long as its intake block is good, an excellent saw. An open windowed 268 replacement piston either OEM or Meteor wakes these saws up even more over the old style full circle windowed piston.
The 670 can really let it all hang out as long as its intake boot holds up. They were the Champ for sure. Otherwise very similar to the 268 in construction with a nicer carburetor than its orange cousins.




Bob = Pistons fully interchange on the 670, 268XP, and 266XP. In OEM, all of them supersede up to part number 501659403. From the Mahle factory in Brazil.

266's originally came with a full skirt piston. Last I knew Forester had a decent copy of that one. Not sure about other windowed AM options. I know that most AM 50mm pistons for these saws are the open port style which don't work well at all in the closed port saws.

    Although there have been variations over the years, the 670, 266, and 268XP pistons are fully interchangeable. All OEM numbers supersede up to 501 659 403 which it still available. It's an open skirt design.
     

670 cylinders were sourced from a couple different places. No significant differences as far as performance goes. There is an early and late though. The neck on the jug was extended to provive rome for a better clamp than the wire job and the boot was also changed at that time. Those boots rarely fail though.

The "Champ" wasn't any different tan the Super II. It had something to do with winning a European logging championship event. Maybe a couple years in a row?