Pioneer 2400 piston/cylinder killed

[cbfarmall]

What do you guys think killed this top end? Piston doesn't have many hours on it near as I can.

Chris B.

 

[hotshot]

Chewed up some debris, burp!

 

[cbfarmall]

We'll see. It's been sitting awhile, no apparent issues. Main bearings rotate smooth, cages appear intact. Lower rod bearing is intact.

 

[Old2stroke]

Piston pin clips still there?

 

[cbfarmall]

Clips are there and intact. Fortunately, I got a 3270 cylinder and new piston here. Same part numbers.

 

[cbfarmall]

I found what ruined the top end. One of the big end bearing cages broke apart. Pictured are 2 pair, the top one is incomplete. All rollers seem to be accounted for.

 

[cbfarmall]

The saw is going back together now with new main bearings and big end bearing, piston, and good used cylinder.

 

[hotshot]

Glad you found it, that saw goes back to the good old days when you could split a rod cap!

 

[cbfarmall]

I can't imagine trying to fix a current modern saw 40 years down the road. I read about ever-changing ignitions and once they quit, they're done for. At least there are options with the points ignitions, ways to make them work, and easy to troubleshoot.

Obsolete ignitions are one of the reasons I won't touch electronic Dolmars.