Jred main bearing question

[bama]

I was cleaning out my 621 and checked the play on the clutch side main bearing. It moves just a tiny bit whereas the flywheel side doesn't move at all. I rebuilt the top end and carb of the saw and didn't split the saw since I didn't think I needed to. Maybe that play has always been there. I can't say that I ever checked it before today. Do I need to worry, or should I look at getting a bearing. I use this saw about 50 hours each year at the most. I have no worries about splitting the saw, but it will take some time(which I am in short supply of). Any advice would be appreciated.

 

[NWCS]

if it was ME, i would replace the bearings.. if one needs it its best to replace them as a set. why have to split it again later for one bearing.. do both crank seals while your at it.

 

[Mange]

Many times carbs are rebuilt without reason.
Is you got bad seals for ex. the air leak can make you think it is starving for fuel, so the carb is rebuilt, the saw show little or no symptoms for a short while then it starts again. I am in deep water here, but I think it has to do with crank case pressure/impulse to the carb.

 

[bama]

I kind of knew that I should replace the bearings, but I was hoping that I wouldn't have to tear the saw down again.

Mange, I did replace the seals. I didn't know if they leaked, but since I was that far, I put new ones in. It runs so good and cuts great, so I hate to tear it down when I need it for this season's cutting. If a mean bearing goes bad, does it take other parts with it? I suppose it would allow air in through the seal if it gets sloppy enough.

 

[NWCS]

i have a TS400 chop saw that lost a main bearing.. the crank started grinding away the side of the block..

notice how the bearing race is still in the block? when i was removing the crank.. about half the ball bearings were missing, the rest were pretty ground down. the little tin flange that keeps all the bearings evenly spaced was totally missing. piston and cyl were destroyed.. it still ran (didnt have a muffler) and constantly shot sparks and alum shavings out the exhaust.. id definatly say it can destroy an entire saw if let go far enough!

 

[bama]

Wow!

That looks bad!! I know I am going to fix this right away. I put too much sweat into getting this saw running to let it get destroyed. Thanks for the picture!

 

[Lawn Masters]

Replace the bearings, its cheaper than one letting go, getting through the transfers and totalling the cylinder and piston too, cause then you'll be looking for a good used set, I believe the 621 parts are pretty much NLA.

 

[NWCS]

heres the piston and cyl from the TS400. this is from not changing air filters.. abrasive dust took the bearings out. this chop saw was taken from a construction companys trash pile.. and you can see why it was there..

 

[Lawn Masters]

Looks to me like the Nikasil literally peeled off the cylinder walls just below the intake port. good reason to actually change the air filter once in a while. Could you post a better pic of that piston itself?

 

[bama]

Well, I tore the saw apart and put in another crank with good, used bearings. It was a lot of work, but it tightened up the slop right away. Should be good to for years. After all, it is red!