125-200cc help please,broke my bike! 3 quick questions.....

1)hi guys,please can someone help me,i was changing my head stem bearings in my 2004 cr 125 and i did rookie mistake and knackerd the top two lines of thread on top clamp STEM,ive been looking at part list and i cant find which forks are fitted to my bike,i messured the fork tube and its 54/55 mm diameter,as is the bottom clamp.on ebay theres some clamps that are off bigger bikes but say there for 45 mm forks,even though they look the same??are forks messured by internal leg or outer leg?
2)anyone got bottom clamp and stem for 04 cr/wr125?

3)can anything be done to fix the thread on top of stem?

Forks are measured at the chrome sliding tube not the cartridge. Use a thread file to clean the threads on the nut or stem. http://www.google.com/products/catalog?client=safari&rls=en&q=thread file metric&oe=UTF-8&um=1&ie=UTF-8&tbm=shop&cid=11371832083853107905&sa=X&ei=b0-1TtKBLouFtgfyr5i_Aw&ved=0CGQQ8wIwAQ#ps-sellers

If its just the nut like your post says then run to your local machine shop and have them run a tap through it, easy. But since you are trying to buy parts i am guessing you mean the stem threads are damaged? Like doug said you can just file the threads to repair them, OR... if it is the top two threads and you cant find a file, just grind them off with a belt sander or angle grinder. Go just past the last bad spot, grind a chamfer also to make the nut start easy and your good. Depending on how much stem you remove you may not have a full nut when you reassemble so you might have to back off the torque when tightening. Ive done this on old swingarm bolts and axles that have been pounded out to many times.

thanks guys,i think monday im gonna call a few local machine shops to see if they can fix it for me,ive no confidence in trying to fix it,if i make it worse ill never get my bike going again!i cant afford a new one (300 quid)and theres none on ebay.(i brought one but it was posted a week ago and it looks like im not going to get it as seller has offered refund already).