250 99 250KX Carb Rebuilding, Screws Stuck

So I took apart my bike for standard maintenance today and have a couple questions as this is the first time I am doing this.

#1 Is this a good spark plug https://www.amazon.com/gp/product/B000C5M2MW/ref=ox_sc_mini_detail?ie=UTF8&psc=1&smid=ATVPDKIKX0DER ? This is a direct replacement for the one that was in it. If not what is a good one?

#2 There is two screws holding the the cap that has the throttle cable running through it, the screws are tight AF and it rounded off two of my Allan keys. Any tips on removing these without stripping the screw or my tools? (See Pic)


Use a set of long nose vice grips if you can get a GOOD grip of them,
Make sure there's an Allen key in it before you squeeze it!!! once out replace! Failing that you could gently drive a slightly oversized impact rated Torx bit in and hopefully turn it out with that!?!
Last edited:
Cut a slot with a hacksaw and use a screwdriver. DUN
That would work, my plan was to take just the carb to my buddy's house and clean it up in his boat workshop. But I am just going to take the whole bike over because he has tools meant for this type of work. But if we cant get it, I will probably do this.
Hard to tell from the pic, but if you have the space, a good set of side cutters gripping the outside of the screw quite often does the trick.