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Im rebuilding my yz and am having a little trouble getting the old crank bearings out of the cases. I wanted to know what you guys use to remove those bearings.

Heat up the case with a heat gun, or propane torch.

ive never messed with a yz250 so i cant offer any real advice. but it wouldnt hurt to have a service manual to see the correct procedure. mapgas is a good tool if you understand how to use it, but it does get real hot and could probly warp stuff if you dont pay attention.

I rebuilt a YZ250 a year of so ago and used a socket and hammer to drive out the main bearings. Came right out.

HRC thanks for the tip I will try that and see if it works. I have a service manual and it says to use a bearing puller but I would rather not buy the tool and use the money for other things

if you cant get them out theres another option. about 4 years ago i made freinds with a mechanic at the honda dealer. he took all the bearings out for like $30. it was good deal considering he took out the bearings for the tranny and crank. then i put the new ones in myself. becareful though, some dealer mechanics are dumbasses

Throw the cases in the oven on 200 degrees celsius,bearings facing down,they will all fall out within a few minutes,worked great for me last winter,I had the new bearings in the freezer and they dropped in without a problem as well while the cases were still hot,it really works great,just get it done fast while the wife/girlfriend is out

bbq plate works good to

will the dust and oil seal drive out with the bearings? when I get them out I am going to heat the cases with a propane torch and freeze the bearings, also im going to set my crank up on a lathe and polish the shaft to get the bearings to go on a little better

caseyracing222 wrote:will the dust and oil seal drive out with the bearings? when I get them out I am going to heat the cases with a propane torch and freeze the bearings, also im going to set my crank up on a lathe and polish the shaft to get the bearings to go on a little better

What way are you trying to drive the bearings? They are driven out towards the inside of the case. The seal is removed towards the right side cover on one side and the stator on the other. If you're trying to drive the bearing out towards the seal, there's your problem.

Get some dry ice and the bearing will fall in there. No need to heat the case unless it won't go, then I'd go though oven route.

Stick your crank in the freezer for a couple hours and it will drop in too.

Best of luck.

Im driving the bearing out the right way but the oil seal is right up against the bearing and I cant get it off. I havent tried getting the stator side bearing out.

Ok I got the clutch side bearing out but I am going to have the local yamaha shop take the other bearing out, press in the new bearings and seals, put my gears in, install my new crank and put the cases back together. I am running out of time to get this motor back together so while the bottom end is being put back together I will ship my top end out to get a new sleeve and will have my buddy reshape the dome on my head and mill it for more compression. thanks again for all the help

putting everything back together is usually the easy part, and typically no special tools are needed. if you cant get all the bearings out, i would have the dealer pull them out and you put everything back together. its your choice but it will save you a bunch of money.

I would need a puller to get the other bearing out and I have alot going on all at once and dont have much time to work on it so I am just going to have Yamaha do it plus I know the guy pretty well and can get a good deal