exhaust nuts rusted to nubbs

hi guys, so im trying to get the head off my aprilia atlantic 125 and i cant get the exhaust off as the nuts are rusted away and unrecognisable as nuts..they are meant to be M7 so 11mm i think....
anyhoo, have you guysa any suggestion as to how to get them off ? there is very little space to work aroung them, very hard to get to
also, on taking pics i see a pipe i cant ID, what is it and will i have to remove it
Through a rigid, flanged duct connected to the head,
air reaches the exhaust connector so as to release
oxygen to the unburnt gases before the catalyzer, by
thus favoring a better reaction of this last component.

cheers rob

 

Give them a good wire brushing and you may find that you can get them off. Below the rust, the nuts must be OK as the exhaust is still held on/

They are most likely to be M6 nuts and will take a 10mm socket. If you can find a 10mm, six sided socket you may have half a chance of getting them undone. Don't try a 12 sided socket as you'll round the nuts off even more.

 

cheers, i upped a pic as its well past using a socket.. of any size, i think mole frips but no space, same with cutting or grinding it away,.. nightmare

i see that pipe in the pic is the SAS pipe, some sort of vent, and il have to remove it ..
cheers rob

 

here you can see just how rusty the nut is

 

as said above use a wire brush to see if you can get them looking like bolts again, then wd-40 them and leave it over night. Wd-40 them again in the morning and try using a socket or mole grips to remove them.

 

ok doaky.. cheers chap

 

Yikes, if all else fails, might be best to have the lump out, cut a slot into whats left of the bolt head, use an impact driver to loosen it. Should then allow you to turn the pipe to get at the other bolt head and do the same. Hopefully.

 

Have you got access to a butane torch or blowlamp? You'll probably need some serious heat to get those to loosen off too. If you can get them good and hot, you may find that the complete stud winds out complete with the nut.

 

plusgas and a socket should do the trick.

 

I'd go with Merlin, you need some HEAT!

 

thanks guys, i might pop out and get a blow torch but then, its a bit dodgy as theres quite a bit of petrol kicking bout the lines, tank etc, first il try brute force, the issue is space, theres none, lol..

is it easy enough to fit new studs as i might have to cut into them if all else fails ?

as stevep says, it would be nice to have the engine out, but as its the exhause thats stuck, its probably not possible, it snakes round the frame, il no doubt get it, its just a bit of a pig,

its so tight for space, i cut my hand to shribbons, as its been ages since i worked on any sort of engine that i forgot, and came in, went to wash my hand and dumped lots of liquid soap on and wow, the pain..
i shrieked like a little girl my missus was very sympathetic tho, her laughter helped a lot

 

good luck with the nuts.
On the subject of the second little pipe- it looks to me like a built in catalyser thingy. You might get a performance hit if you disconnect and blank it off with a plate. But check where the other end goes and what it´s connected to. or ask someone who knows what they are talking about.
I'm clueless with 4 strokes......

 

If all else fails with the nuts, dremel them off, remove the pipe, then the entire barrel. then you can put the cylinder in a vice, heat the flange with a torch and attack the stubs with a pipe wrench.

 

yeah it was an SAS pipe, as you say, its a catalytic thingy..i got that off ok..

on looking at the exhause closley, it might fit between the frame to get it out after all, but then, the head has to slide all the way up the head studs..hmm.. would you believe it, the allen bolts on the exhaust have siezed lol ..but they are easy to access, so im working on them..
cheers rob

 

If you remove the shock you might be able to get the barrel pointing somewhere where ther's nothing to stop it coming off.....
Just an idea-
I don't envy you.

 

yey, got the head off !
there was a break and jubilee clip where the downpipe attaches to the exhaust, i saw it once i got the silver heat shield off it was a bit of a struggle but got there

 

Well done!

 

It's called Spanner Rash and we've all been there! You're not a mechanic unless you've split at least six knuckles undoing nuts, drunk tea with brake fluid in it and had several mouthfuls of petrol, followed by maybe setting yourself on fire a little bit or singeing your eyebrows off through using Easy Start on a backfiring engine. It's stuff like this that turns us into battle-scarred veterans.

 

Well, i got the "nuts" off the head...not much left of them, it was tricky but saved the studs..

 

Well done you