Main bearing

[WozzA]

Before I go wacking it with a BIG kadonger... 
Whats the best way to remove the Drive side main bearing outer shell from the case??? 

[Brian]

Heat the case up Wozza. Use whatever you have to heat it, the oven (if she's not home!) or whatever you have, get the case too hot to hold, so spit sizzles on it and the bearing will fall out. Have a piece of wood handy so if the bearing doesnt fall out you can give the cases a bang face down on the wood.

Use the same heat principle when you put the new bearing in. You will find the new bearing will just drop into the case.

[WozzA]

Thanks Brian...  I was unsure but thought heat would be the way to go to get it out..
you say the same process to replace it... BUT wont the heat in the cases bugger up the new rubber seal #67-674 behind it?    ????

[orabanda]

Wozza,
Fit the seal last; after the case has cooled to ambient temp.
Richard

[Brian]

Ambient temperature means cooled down Wozza, its those sandgropers trying to confuse us with fancy language again 

[WozzA]

Yeah ... I'm not that dumb...  ( or am I ? )  
What I'm looking at is a 1/8th seal with a metal cage that is fitted in behind the bearing outer shell...
EDIT:
OK I see where I went wrong..  Doh...  
Just went & took a picture, the seal goes in from the outside AFTER the bearing outer shell is fitted, & fits up against the outer shell..

I just prodded the seal out & as there is a lip of the bearing shell I was thinking it had to go in first..  

maybe I am THAT DUMB after all..   sigh..    thanks guys..  

[chaterlea25]

Hi Wozza,
Be Careful 
Do not push the seal in too far 
It will rub on the bearing inner cage if you do
The outer of the seal should be flush with the outside of the crankcase
Looking at your pic there may be a washer between bearing and case????
Usually the bearing lip is not seen from the outside  ( As far as I remember!!)

HTH
John

[WozzA]

Hi John... thanks for your input..  
that lip in the picture is the bearing outer shell...  
there is a small gap between that lip & the inside lip of the cases...
thats why I thought the seal sat in that gap..

When I get the crank reground I think I better get someone smarter than me to rebuild the motor..

[WozzA]

I've removed the bearing shell as suggested... & it just fell out..   
there was a gap of approx between 1/16th" to 1/8" behind the shell which looks like the bearing had not been pressed in fully ???

[muskrat]

 Or it was a little loose in the case and moved when the cases were split.
Cheers

[WozzA]

Thanks Musky...on reflection thats what must have happened...   
it only had 2 shims on the crank behind the bearing,
so it must have dragged the seal into the gap when I removed the crank..
ALL GOOD...  I got new bearing & seal to replace them..   wink2
 

[trevinoz]

Wozza,
                Did you manage to get the correct NF206 bearing?
They seem to be a bit hard to get in this town.
Lucky I stocked up some years ago.

Trev.

[WozzA]

Yeah Trev...  Modak has them... $50

[orabanda]

I like the main bearing SRM has recently supplied me; it has a plastic retaining cage for the rollers.

The beauty of this, in comparison to having the steel retaining cage, is how it makes setting of the crankshaft end float very easy.

With the plastic cage, the rollers can be pressed out by finger. Then a bearing puller plate can be used on the shoulder of the inner race of the bearing, and removed without any damage.

The bearing will also assemble easily;then shimming for end float can be changed, and the bearing fitted (again).

Too easy!

Richard

[Brian]

Wozza if you get the bearing from Modak make sure it is a brand name bearing and that the bearing make is stamped in the bearing.

If it comes in a plain box or doesnt have the brand name stamped in the bearing dont use it.

Unfortunately there are some very poor quality bearings on the market and even worse they are starting to turn up in brand name boxes. Doesnt matter a lot if its a wheel bearing for your lawnmower but you dont want one in your engine.