Need help installing crank main bearings.

[i ride]

I split my cases to install a new crank and main bearings. Everything is going smoothly soo far, but I'm having trouble installing the main bearings. I'm practicing on the old bearing so I don't screw up my new bearings. But I put the case in the oven(and another time I used a torch) at 250 degrees for 15 minutes then I freeze the bearings for 2 hours. And everytime I try to put them in, they don't really drop in, i kinda slightly push them alittle then they stop 1/2 through. And I tried this like 4x today.

What should I do? Is there any way to make sure they go completely straight? Is there any thing in my technique I should change? Any tips or anything would be helpful.

[gscx]

Using a torch will warp the case.

[dirt_rider_39]

you should be putting the bearings into the case sides first, then freeze the whole crank assembly and heat the bearing then drop the crank into the case/bearing side...if it dont drop in do not hit the crank as you can knock it out of alignment...you will need to pull it through with a crank puller..

2 hours isnt long enough in the freezer...it should be so cold it starts to form frost when you take it out...250-350 for the bearings...

Also make sure there are no nicks on the shaft ot that can hold it from going together smoothly..

[mxn4life]

I split my cases to install a new crank and main bearings. Everything is going smoothly soo far, but I'm having trouble installing the main bearings. I'm practicing on the old bearing so I don't screw up my new bearings. But I put the case in the oven(and another time I used a torch) at 250 degrees for 15 minutes then I freeze the bearings for 2 hours. And everytime I try to put them in, they don't really drop in, i kinda slightly push them alittle then they stop 1/2 through. And I tried this like 4x today.

What should I do? Is there any way to make sure they go completely straight? Is there any thing in my technique I should change? Any tips or anything would be helpful.

Press them in.

[juliend]

Yes, leave the bearings in the freezer overnight. Heat the cases to about 250 in the oven for 15 - 20 minutes. If you have to tap the outer race just a bit that's no problem. You can use the old bearing laid over the new one and start gently tapping. It will go.

Once you have that done, repeat the process for the crank like Dirt Rider said above.

[zwazuski]

Does anyone know if I freeze the bearings using a can of air tipped upside down do any damage to anything. I used a can when I put in my clutch basket and it worked great. I just don't know about that stuff on bearings.