How hot for bearing replacement

[98cr500rider]

Question is how hot in degrees Celsius do you need to heat the engine cases to remove and install new main bearings?

I often read about heat them up enough and the old bearings will fall out and new ones out of the freezer will drop right in.

I don’t do this every day so just to be clear is this true quite literally or an exaggeration, will they drop in without driving them in with a drift or is this myth?

If so how hot is enough and still safe for the cases, I intend to use an oven with a temperature gauge so please be accurate if you know, not just hearsay.



Just out of interest has anyone got a video link of this being done?



Thanks for any info on this


.

[AlisoBob]

Put them in the oven at 300 degrees for 30 minutes... nice and toasty.

[2strokeforever]

both mine dropped in, i used a toaster oven at 350f, and i froze the bearings too
and if you do need to tap them in make sure you are pushing against the part thats going in, not tapping on the middle of the bearing if youre putting them in the cases

[fastkart]

300*F is about 150*C

[100hp honda]

never read any info regarding the honda. direct info from ktm manual says: heat housing halves to 100-150 C. bearings should fall out on their own at 150C. if they do not then tap housing lightly on piece of wood. clutch arm bearings might need blind bearing puller. they rarely wear out though so might not need to replace them.

[2strokeforever]

good info
id always "just go" and make it happen

[AlisoBob]

Are those KaTooM cases cast or forged?

[100hp honda]

cast like jap bikes im assuming. hell i dont know

[Roostius_Maximus]

if you use map gas or propane carefully, you'll see the aluminum sweat, once that goes away its ready

[south central hoon]

I've never needed much heat. it's a slight interference fit. just tap them with a bearing driver....

[2strokekyle]

Don't just hammer them in/out, it will screw up the bores the bearing rides in. Hot cases plus cold bearings = no interfereance, at least for a second.

[dannygraves]

Don't just hammer them in/out, it will screw up the bores the bearing rides in. Hot cases plus cold bearings = no interfereance, at least for a second.

put the bearings in teh freezer over night and the cases in the oven at 300F

[blackz34]

So you put the case in the oven with the other bearings in?