Cs1200 battered pto case bearing

[Robin Wood]

Felt some play on pto side, so i opened it hoping its not a wallowed case and for once in my life luck is on my side. Pto side seal let some particles in from play, a portion of piston on intake side is gauged. Case got rubbed with crank going side ways from bearing play

What would cause bearing cover to fail? Thinking of going with roller bearings on both sides, it came with 6304 ball bearings and looks like nu204 roller bearing has same dimensions with nylon cage. Hope some experts can give opinions

 

[rmh3481]

May have just been a bad bearing. That happens once in awhile. I dont think I would use a roller bearing on the pto side, I would replace all the bearings with oem and a set of new seals and call it done.

 

[cbfarmall]

Saw looks like it has some miles. I see sealant around the cylinder base--doesn't look factory. That piston also looks cracked on the skirt. Better replace. Don't try to use roller bearings unless you can control the thrust. Stihl 090s have plastic washers for endplay. Remingtons have thrust washers on each side of the crank. Poulan 3400/3700/4000 use the roller bearing depth to set endplay. Even older Homelites have a roller/needle on end, and a fixed ball bearing on the other to control thrust. They are all designed for this. Your saw is not. New bearings and make sure the fit is tight.

Chris B.

 

[Robin Wood]

Thanks for the input guys
Chris you're talking about side to side play right?
The roller bearing im after will let inner ring to move around, so i guess thats a no go

 

[Hdtoolmkr765]

Robin, that is correct, Chris is referring to end play. A roller bearing would typically have a slip fit on the crank shaft, so there would be nothing to contain the crankshaft in its intended position. With ball bearings, they are a press fit on the crankshaft, that is how the crank stays in its intended position. There are a few exceptions such as the 200T where it is a hybrid bearing with rollers in place of balls, but it is still a bearing with an inner and outer race that is a press fit on the crankshaft. I agree with above, put OEM bearings and seals in it.

 

[Robin Wood]

The idea came to me as these big saws really experience massive load on the pto side especially when running long bars, roller bearing has more than twice load capacity but only downside is like you guys said making it stay together than going sideways. If it could be made to work it'll probably run for the rest of its life without trouble