The head bearings on my EVO need replacing but the inside shoulder of the top bearing is seized onto the shaft and will not budge ! We've tried hitting it with a hammer with a piece of wood inbetween to prevent damage, heating it and using a penetrating oil but it isn't going anywhere. And ideas as to where we can go from here ?

Two thoughts (assuming that you've checked there isn't any other more simple reason its not moving, this is quite unusual)

• Use an aluminium dolly instead of wood to transfer more of the shock load (wood is a good shock absorber)
  

if that doesn't work.....

• Get some local targeted heat onto the inner race of the bearing as the resulting expansion breaks the seizure, use some penetrating oil before it fully cools.
  

Dom

If you can get to it with an angle grinder, just cut in in two but be careful not to damage the shaft.

Thanks for the suggestions, I will try the aluminuim tomorrow ! I cant get either the bearings or the steering shaft connected to the bottom yoke out of the frame though due to the seisure, so heating the shaft is a tad risky !

That is a very unusual thing

Generally that is a fairly loose fit and the stem usually just drops out of there with no effort

Can you post a picture of the stem ? Is there visible rust/corrosion between the bearing race and the stem?

as already stated you need to heat inner race to expand it ,not the shaft as that will have the opposite effect to what you need

I don't know, there is no compression fit on that bearing, it is not pressed onto the stem like the lower race

If compression/press fit is not the cause then thermal expansion would not be the solution

I spoke with a fellow who removed the top nut from the top triple clamp and thought the stem would pop out, didnt know there was a nut under the top clamp