Exhaust header studs snapped!

[chappers2a]

Help needed! Due to an injury I am currently unable to ride so I have spent my time fettling my bike, a 2016 RT. All was going well until I decided to fit the Black Widow stainless headers which had been lurking in my shed since 2020! Despite frequent applications of WD40 to the header nuts in the week prior to starting the work and application of heat just before my first attempt to loosen the nuts...disaster- 3 out the 4 seized nuts snapped the studs.
I drilled one of the broken studs to insert a stud extractor which eventually snapped too!
I am at my wits end and wonder whether it would be easier to remove the heads and take them to an engineers to have the studs removed and possibly have helicoils fitted if there is damage.
Does anyone have any tips that may help me please? Yours despairingly...

[David.]

Have the studs sheared off flush with the head or is there any stud left to which a nut could be welded on.

[chappers2a]

Hi David, there is a little bit of stud projecting on two of them. whether it is enough to weld a nut on I don't know. Plus I don't have any welding equipment or knowledge of. Unfortunately the bike is not able to be ridden on the road so I cannot take the bike anywhere.

[David.]

I appreciate your lack of welding equipment and knowledge of but I believe that a nut fitted over the stud and welded on the inside is the way to do it.

[Stu]

You have been very unlucky to snap those as the nuts on my 2016 are brass!

Anyway as David has said welding is the way to go

Do you not know anyone that has a welder?

[David.]