I was cranking down the nuts like a gorilla because they've worked loose before...SNAP!
Doh, snapped the 8 mm stud clean off.
While thinking about how to recover and if I'd need to remove the head, I had the presence of mind to remove the other nut before the Loctite set, but then I realized there's about 3/8" of the snapped stud when the muffler was removed. I got it out with vice grips, so crisis averted.
Now the question: Which end of the stud goes into the head, the shorter or longer?
(The stud has an unthreaded divider in the not-quite-middle.)
Also, concerning the use of Loctite on the exhaust fasteners...guess what's used to help loosen up fasteners held with Loctite (or any thread locking compound). Yep, heat. Guess where a lot of heat is on an engine. Yep, the exhaust port. So the moral of the story is, normal thread locking compounds don't do much good on exhaust fasteners. I actually use an anti-seize compound on my exhaust nuts and have never had one fall off or get loose. The exhaust nuts are long in order to have as many threads engaged as possible to help keep the nut in place. If regular nuts are substituted, then all bets are off. If it helps make you feel better, lock washers under the nuts can always be used.
I've ordered a new set of studs and nuts, of course.
Yeah, the Loctite seems a bit superfluous on those, but, I figure it can't hurt.
As to anti-sieze... Do you use the silver paste stuff? I've used that between the rotor and my wheels on the truck to avoid rusting, but haven't applied it to the scooter.
Yeah, the silver suff. Been using the same tube for the last three and a half decades. I also have some of the copper stuff, which I prefer, but haven't seen it in the last four decades. It's buried in the garage...somewhere.
As previously stated, the short end of the stud goes into the head. The reason is so that the un-threaded portion can bottom into the head, allowing you to provide a little torque.
On the nuts, for exhaust studs, stover mechanical lock nuts are the preferred fastener. They are a nut with tight cut threads that has been slightly ovalized. It forms to the threads as you tighten it down. It's a one time use nut though.
They are typically used for high heat, vibration locations. It's an older version of lock nuts prior to nylock nuts. And obviously, a nylock nut wouldn't do so well in high heat applications. Stover nuts are common on turbo applications for manifolds for the same reason they are popular for high vibration exhaust manifolds and pipes.