Left hand drill bits have saved me on a number of occasions.

Whilst they may sound like the kind of thing you'd send an apprentice to get from the stores they do exist and are bloody useful:

http://www.ebay.co.uk/bhp/left-hand-drill-bit

They drill in the "undoing" direction and will usually start unwinding rounded screws even before the head is drilled off.

I'm not sure if you can get a drill in to access the exhausts or if they are the best approach to your specific problem. Are the socket caps fasteners that you're trying to undo bolts or a kind of nut on a manifold stud? (I can't recall and my bike is not to hand).

Hi, they are smooth round head with a allen key 'inner'

http://www.xt660.com/<a href="http:/...CA2BG2NQ-1.jpg[/IMG] http://www.xt660.com/<a href=

Gotta be a way. Reckon Yamaha did it as part of anti tampering legislation!

In the end I filed the 'nuts' off.
Then I grabbed the studs with mole-grips to loosen and remove.

Replaced the studs with stainless grub screws (allen key driven bolt with no head), A shed load of Copaslip.
Used domed nuts to finish the job.

Hardest bit was filing with almost no elbow room.
first 2 nut/sleeve things I filed 2 sides flat until thread was just showing.
the second 2 I was getting bored/frustrated so just filed one side and whacked off with screwdriver and hammer ;)

Was scared to overtighten when replacing, so took about a week to bed in the exhaust gaskets with constant gradual tightening. (really should invest in a torque ratchet thing).

Similar method to remove rounded rear brake rotor bolts, filed flats on and grabbed with my trusty mole-grips. My file too has been very helpful recently!

Hi mrfijjitt,

Glad you got yours sorted. I've gotten myself into a similar dilemma with my exhaust bolts. I've gotten all but one loose. looks like I may have to go down the route of filling the last nut off.

I was just wondering what size grub screws you used?


Sorry for the bump of such an old thread, it just seemed like more sense than starting a new one for exactly the same issue.