Exhaust bolt broken off in Head

Argh!
Trying to take the exhaust off my K3 I managed to break the head off the bolt going into the head of the engine. There is about 5mm of bolt left sticking out still. I would appreciate any suggestions as to how to go forward as I don't want to have to take the head off.

As the bolt is aluminium I'm not going to be able to weld a nut onto the thread (as I can't weld aluminium)

I have so far soaked what is left with Plusgas. My thoughts were to now get a source of heat (such as a one of those kitchen blowtorch things) and head the bit of bolt up, then attach mole grips and hope I can turn the remains of the nut.

Am I doing the right thing?

should be able to as the allen bolts are easier to grip with grips. My advice is suzuki cheese might just crumble under heat but i'm not 100% sure.

[yorkie_chris]

Aluminium bolts? Are you sure about that?

Can you get a proper socket type stud extractor onto the remains?

If so then I've found that repeated heatings of the alloy while cooling the stud works. Stick a bit of potato over the stud.

[northwind]

If it really is an ally bolt, it'll be a piece of p to drill out.

stock bolts are steel.

Originally Posted by yorkie_chris

Aluminium bolts? Are you sure about that?

The bolt that did come out is non-magnetic. The bike I own has no exhaust modification and very grotty pipes - I can't believe the bolts aren't oem. I will certainly be looking around for stainless steel replacements.

I'm very wary about using a stud extractor - if it breaks in the head it will be a nightmare to get out. I think if the heat and mole grips don't work and just break off more of the thread then I will go for drilling and re-tapping.

On second thoughts they were far too heavy to be alumnium. I didn't know you could have steel that wasn't magnetic
I managed to remove the sheared off bolt, but now need to replace it - any ideas of where I can buy 2 good quality allen bolts? (I know suzuki ones will be expensive and cr@p).

[yorkie_chris]

Allen bolts are a really bad idea. Get a stainless stud/cut down bolt and a flanged nut. Put it in with copperslip.

[Stu]

Originally Posted by Aidan

I managed to remove the sheared off bolt,

Well done!
I had the same problem & made it 100 times worse by trying a stud extractor which broke (as you forsaw).
So was it the method you said above, heat, plusgas & molegrips?