Is it worth heating each nut in turn before even trying to remove them, just to help that little bit?

It's worth getting a blow torch or some oxyacetylene and getting them AS HOT AS POSSIBLE.

If they are heavily corroded they WILL break unless you are REALLY lucky.

Seriously. I've had about four XT600E's in my workshop needing the heads removed to get the broken studs out. They were only a few years old and already breaking.

__________________
Did some trips.
Rode some bikes.
Fix them for a living.
Can't say anymore.

Fit Stainless Steel studs and you can get brass nuts which are double the height of normal ones and this combination does not corrode, a little cooper grease and you will be fine for years to come. Just remember to use a 6 sided socket as the brass is soft and you can round them off using a 12 sided socket.

Heating metal will expand that material that is heated (metal)

So I do not recommend heating of the stud.

All metal rusts some (ss) just take longer, so less service of studs. Copper grease no bad thing.

The main problems is the nut rusting onto the stud and this is one reason as to the use of brass nuts also the stud corroding into the cylinder.

I have had several times the problem of nuts rusting onto the stud but have always manged to free them with patiant coaxing. How

Ensure thread of stud is clear of rust where it is possible to access.

Same for the face of the hex on the nut.

Wind on to stud new nut and align with old nut.
This now gives you a greater surface area to which you can apply preasure to release offending nut (with well fitting socket or ring spanner)
Application of releasing fluid days prior to removal will/may help.

If the stud is not moving try a little pressure in reverse this can often crack the seal which is rust and alloy corrosion.

Heating the alloy in just the area around the stud is only going to crack your cylinder head. Maybe heat the engine then spray some plumbers freeze spray on the stud (only) This way one expands the metal on the head and reduces the stud within the thread of the cylinder.

Try some ACF50 to help protect from rust on your bike particularly whilst all this salt is being spread on the roads.

Anyway B/Rev if you were in the scouts you should be prepared.

Good luck when the time comes.

Socks

Heating up a stud that is threaded into alloy to red heat and then letting it cool down before you try to remove it is one of the best ways to get them out of the alloy without damage .But only heat the nut or stud - not the alloy .
The steel expands and then contracts and loosens itself ,furthermore the oxidation and corrosion is burnt away or cracked and any penetrating oil that you apply will now get to work much faster .
Use a small flame like an oxy acetylene torch or one of those small propane plumbers torches .
Then use new studs when you replace the exhaust system.

If you want to get a nut off a stud or bolt that is well rusted on ,wire brush it well to remove as much rust as possible and then heat the nut red hot .Do it fast so that the stud [or bolt ] remains cooler .Then ease the nut off with a six sided socket or wrench . The heat will expand the nut and break the rust film that binds the nut to the stud .
Easy !

__________________
Blessed are the cracked, for they let in the light. - Spike Milligan
"When you come to a fork in the road ,take it ! When you come to a spoon in the road ,take that also ."

Thanks again for the info everyone, it's extremely helpful and appreciated.

It's half amusing really, almost as everyone is speaking in hushed tones about the story of removing their header pipes

Of course it's not really amusing as a cock up here can cause some serious ball ache. Yamaha made a great bike and to have something like this let it down is disappointing.

Anyway, I had a look at my nuts yesterday (ooer missus) and they don't look too rusty TBH, are they out to deceive me and snap the studs anyway?

There's part of my dying to have a go at undoing them but I'll kick myself if I snap a stud.

Hi there !

I wish you the best of luck in removing the studs/headers. Mine were in such a bad state I ended up taking off the cylinder head (on the advice of ted) Which was the best way for me. I think mine were an extreme example though, I was unable to even remove the headers there was so much crud built up around them and I ended up drilling out the studs after each one snapped. I too had used penetrating oil for weeks in the lead up to replacement, but to no avail. Got there in the end though and now have stainless studs, lashings of copper grease, shiny motad downpipes and a fine sense of accomplishment ! Bill