Perfect Grumpy!....There is one more option that does not involve much risk,And ive done this many times when im in a hurry...Again as Grumpy has stressed your drilling must be accurate. Drill the bolt out in its entirety and just helicoil it. Its very common for an exhaust stud/bolt thread to be chewed a little as its a major heat and stress point. Yes its easy for me cause ive got them in stock,BUT if you use this process you can then take it to a Mech or engineer or the like and get him to put in the helicoil. Would be less expensive than buying a whole kit which usualy quite expensive. he may only charge you 25?. The hole should be 1/4 20 from memory and a drilling size for recoil will be 17/64 which you should have in any IMP drill set.. I use helicoils often on Victa 18 handle bar brackets as they are usually chewed out.
