Steering Headbearings XR250L

I've got a '91 XR250L. I'm doing steering head bearings. The link below shows the bottom triple clamp with the steering stem coming out. The inner race of the lower bearing sits at the bottom of the stem on top of a dust seal against the lower triple tree. Its an interference fit. I don't know how to get this inner race off without messing something up. Thought about heat but the race is steel and the stem is alum. so heating will expand the alum. faster than the steel.. What do you all suggest?
Need to get this thing back together..
thanks.
Marc

http://powersportspro.com/partsfish/Displayfiche.asp?Section=103848&ID=558




:think

Hey, thanks for input...
I'm not sure if alum. expands more or less in total than steel but, I understood that it expands faster.. so at a minimum there's time differential where one hasn't caught up to the other.. I'll put it in the freezer now and try messing with it at intervals..

Grind the bearing with what? I have an angle grinder and a dremel but, I'm not sure I'm comfotable getting them thing near that soft alum. Just a couple little grazes would compromise that stem. What do you use?

Ok.. the bearing is off .. but the stem got nicked.. that stem is real thick and the dremel cut through the bearing and did cut a little groove in the stem.. then we took a dental drill head and ground it out a bit more then polished out the edges.. One of the guys helping did say I could flatten it out to remove all of the groove but, I'm just going to put the bearing on and go with it.. wish it hadn't happened but,the guys that helped have way more time messing with way more expensive bikes than this and they say it'll be alright so .. I gotta go with it..
I appreciate the input.. In the future I'll do this myself and just be even more careful..
thanks for the help.
Marc
:mad: