Built a 66" American Long Bow out of Yew, problem is I developed a 2 1/2" set, question can I use dry heat and reflex the ends to increase the speed?  I can leave the bow alone but I figure I may as learn in my growth as a bow maker

Built another.  I don't think you can "un-damage" wood fibers.

Don't do that. Apex is right.

Technical terms are Modulus of Elasticity (MOE) and Modulus of Rupture (MOR).

In oversimplified terms, MOE is the point to which the wood can bend and recover fully. MOR is the point where it won't recover fully, where some of the fibers have ruptured. When a bow takes a set, the MOR of some fibers has been exceeded, and there's nothing you can do about it. Both are affected by moisture content, so more moisture means less strength for both. Set represents a permanent loss of strength and form. Mess with it and you'll make it worse.

You could recurve the ends, but then you'll just stress the wood more causing more set in the working limbs (see Don's explanation) and it'll all be a wash.

If you started with a straight stave and the bow stays at 2.5" of set, that ain't too bad.  Anything under 2" is generally considered real good and when you're just starting out... my first bow had 4".  Learned alot about properly tillering and exercising bows with the first couple.  

OK I get it, build another.  Thanks for the input.

What ever set your bow has in it,it's there.You can't take it out.