how to remove bottom end bearings?

[destey]

I did a quick search and couldn't find much. I have my motor disassembled, case halves split. I just need to remove the old bearings and seals and put in the new ones (I've them all).

I've heard heating the cases in the oven and cooling the bearings to install them, but how do I get the old ones out? Do you need some special puller that grips the inner part of the bearing?

thanks in advance,

[86 Quad R]

are you wanting to replace ALL of the bearing or just the crank? if replacing just the crank bearings, you can use the "heat up the cases" method and simply tap the old bearings out but if your replacing them all then you can use the same procedure but may need to use a "blind bearing puller" on particular bearings although at times i've had them to drop right out.

use the "heat up the cases" method to re-install the new bearings aswell.

[destey]

Anyone ever tried heating the cases and cooling the bearings after it comes out of the oven with some water or maybe that computer dust spray turned upside down?

[86 Quad R]

that's not nearly as effective. freezing them gets to the core and condenses the molecules better. allowing them to shrink better. :cool:

[destey]

Originally posted by 86 Quad R
that's not nearly as effective. freezing them gets to the core and condenses the molecules better. allowing them to shrink better. :cool:

You're talking about removing them right? Would cooling them shrink both the case and the bearing the same amount resulting in just smaller everything, or does the bearings shrink more than the cases yielding a smaller bearing OD that'll come out easier?

thanks for the assistance!

[86 Quad R]

nope i'm referring to installation. heating up the case halves with the bearing installed will allow the bearings to almost drop out of pocket due to the fact that aluminum will expand about 4 to 6 X's that of the steal of the bearings. installation of the bearing by heating the cases and freezing the bearings will make the process almost effortless. :cool:

[destey]

Aluminum expands more than steel, makes sense. So to get the old bearings out just put it in the oven at 200F for an hour? this is so much easier than the snapon puller I was eyeing

[86 Quad R]

yup and depending on how much ya work on such stuff, you may wanna consider a puller like the one harbor freight offers. reasonably priced too.

[Honda 250r 001]

set the cases on a flat surface and get a socket the same size as the inner bearing race. and hammer away.

[250r grave yard]

Originally posted by Honda 250r 001
set the cases on a flat surface and get a socket the same size as the inner bearing race. and hammer away. what he said

but do heat the cases and freeze the new bearings before putting them in

do the same with the crank

[86 Quad R]

a side note: the only bearing that may give you trouble and may need the blind puller is the really small, thin, flat roller bearing for the shift drum but, that particular one hardly ever needs replacing.

[SuperSherman]

Honda 250r 001 said it. Don't waste your time or gas to heat the case up for removal. Just smack the heck out of them. Freeze the new ones and heat the cases for install though.

[86 Quad R]

Originally posted by SuperSherman
Honda 250r 001 said it. Don't waste your time or gas to heat the case up for removal. Just smack the heck out of them. Freeze the new ones and heat the cases for install though.

the older one gets the more one comes up with ways to make things easier on ones self........... i personally preferr to heat the cases and have the bearings fall out on the table. takes all of 5 minutes per half. :cool:

[destey]

I heated the cases up to 275 for an hour and a half and got all but 3 bearings to come out (had it in for 225 for an hour but that only got 2 bearings out).

Still gotta get the thin needle bearing that the shift drum sticks into. Also stuck is the bearing where the shift rod comes out of (blind hole) and the shift lever bearing itself. All seem to be very well entrenched.

Ordered a $13 pilot bearing puller from harbor freight, hopefully that does the trick. If that doesn't work, i don't know what to do.

Anyone else end up cutting up the bearings?