Sweating main bearing in...need help

Teej317
Posts
678
Joined
4/30/2010
Location
Colstrip, MT US
Fantasy
1909th
3/27/2018 7:21pm
I'm trying to sweat a main bearing in using an oven and dry ice. Put engine case in oven for about 20 minutes at 275 degrees. Bearing was sandwiched between dry ice for well over an hour. Bearing will not drop in. Tried tapping it a little but will not go. Can't even get it halfway in. I've tried this a couple times now.....what am I doing wrong?

Bike is an 05 RM 250 and the main bearings are OEM.
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eeazye
Posts
246
Joined
10/22/2009
Location
Akron, OH US
3/27/2018 7:34pm
You need to turn the heat up. I bury the knob on my oven when I’m doing case bearings. It usually hovers around 400 degrees.

Also, you get more bang for your buck with heat vs cooling. You’ll get 2 thousands or better stretch as opposed to maybe a half thousand shrink with cooling. That requires a lot of time in dry ice and quick action when installing.
Micahdogg
Posts
1267
Joined
1/3/2011
Location
US
3/27/2018 7:44pm
Yeah I use $350. Once the case is good and hot, you can hit it with a propane torch for a little extra heat before plopping it in.
Teej317
Posts
678
Joined
4/30/2010
Location
Colstrip, MT US
Fantasy
1909th
3/27/2018 8:24pm
Thanks for the tip.....350 for 20 min worked. A light tap and it dropped in.
slipdog
Posts
10043
Joined
7/25/2009
Location
Nor Cal, CA US
3/30/2018 9:09am
I just use a press and none of that is necessary

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