REPLACING BEARINGS

Old 05-18-2007, 12:10 AM
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Default REPLACING BEARINGS

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?
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Old 05-18-2007, 06:04 AM
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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).
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Old 05-18-2007, 04:28 PM
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If i may add something to this ,

oil the new bearings before putting them in.. it will help them move into place.

if you are removing bearings for servising and then putting them back its a good idea to oil them before you heat the crank case , this will protect the inner race if its polymide from excess heat ...

M
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Old 05-19-2007, 05:57 AM
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[QUOTE=TomB]


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.

THis is another example of the side with the Balls visible!
Attached Thumbnails REPLACING BEARINGS-70690rvo.jpg  
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Old 05-19-2007, 06:16 AM
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[QUOTE=itchy b]
Originally Posted by TomB


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.

THis is another example of the side with the Balls visible!
i knew i was gonna incur the wrath of a balls joke sometime or another! trust you joe to do it lol
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Old 05-20-2007, 12:46 AM
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Originally Posted by MassiveMods
If i may add something to this ,

oil the new bearings ..
if you are removing bearings for servising and then putting them back its a good idea to oil them ......

M
This might sound stupid!! Why will you remove bearings for servising?
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Old 05-20-2007, 02:06 AM
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[QUOTE=TomB]
Originally Posted by itchy b

i knew i was gonna incur the wrath of a balls joke sometime or another! trust you joe to do it lol
I kept that pic just for such an occasion
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Old 05-20-2007, 02:07 AM
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[QUOTE=itchy b]
Originally Posted by TomB
I kept that pic just for such an occasion
Btw i just couldn't resist the opportunity!
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Old 05-20-2007, 07:41 AM
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Originally Posted by casimirsa
This might sound stupid!! Why will you remove bearings for servising?
It's really only for replacement, to change them when they are worn.
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Old 05-20-2007, 06:02 PM
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Originally Posted by casimirsa
This might sound stupid!! Why will you remove bearings for servising?

Sometimes they may feel gritty or gummed up .. you can take them out and soak them,, if you clean them inside the engine 1 you wont get to clean them as well and 2 you risk flushing debris into the motor,...
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Old 05-20-2007, 08:29 PM
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Gritty bearings cause vibration and put extra load and stress on the motors. All not good.
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Old 05-20-2007, 08:33 PM
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If the bearing gets gritty, that means the bearing's life is done.
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Old 05-20-2007, 08:36 PM
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Originally Posted by Team Kamikaze
If the bearing gets gritty, that means the bearing's life is done.
Yes, then it goes to bearing heaven and plays shuffle board with its old friends.
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