Okay guys i really could use some info. today i'm working on a 250 by buddy rebuilt the top end on. when he was removing the thermostat housing it broke in old head. so the sun came out and i got back working on quad got the new housing, got everything back together. i started filling the water and was like wtf this is enough water to fill the whole case and nothing was leaking. went to fire motor water started coming out of oil pump tube ect. i had no idea what was going on so i started rebuild again by time i got back up to the head i noticed a big threaded hole under the camshaft. im guessing there was a set screw there that was supposed to get swapped in from old head but didn't. i need to know what goes here? what its called? can i find a replacement? where might i find one? or am i going to need a new head?

 

My Joyner 250 buggy has the same head. You need to put a plug in that.

 

damn i think you figured it out. s%!t all the research for nothing. bang hit the nail on the head without even trying. I know its a plug. think before you speak. what are they called plug. I tried local nut and screw stores and they have nothing with this thread and don't really carry metric set screws.