Originally Posted by casimirsa
I have been pondering over the subject of replacing bearings in a motor for a long time!
My questions is:
1. Is it better to replace the bearings by knocking them out or to heat up the crankcase?
2. If you replace the front bearing with a METAL seal bearing do you take out the inside seal or not?
3. If you replace the front bearing with a RUBBER seal bearing do you take out the inside seal or not?
question 1 = yes, heat up the case to about 200 degrees celcius or more, (pre heat oven) then let it sit int he oven for 5 or 6 minutes, then tap it out with anything.. peice of wood, large diameter allen key etc
question2 the inside bearing has both shields removed with the balls visible, and facing the backplate.
question 3 the outside bearing (front) take one sheild of and place the balls visible, facing the backplate, leave the outside rubber seal of course
ps when i say "balls visible" i mean this. look at the bearing notice it has the "cage" which holds the balls, one side covers the balls the other side has the balls exposed, ie visible. this is what i mean by the "balls visible" side.
now to put the new bearings in, pre heat the case again, this time a bit longer (without carby preferably) ie heat up for 10 or 15 minutes, then put the new bearing in the crank (the large internal bearing ) and drop the cold crank and cold bearing into the hot motor. pull the crank from the clutch bell end so as to make sure the bearing is sitting striaght, then quickly pop the outside bearing into the case. MAKE SURE WHEN YOU PUT THE SMALL OUTSIDE BEARING IN, THAT THE CRANK DOES NOT DROP OUT! lol. if necessary hold the crank with a peice of wood or some heat proof cloth or something.
it is also a smalrt idea to wear pit gloves whilst you do all of this, as well as obviously, holding the hot engine with ample amount of towel to stop burning yourself.
pps; take the rubber carby boot of just incase it melts or some weird stuff happens
(like i said above, preferable to take entire carb of).