Ok so this is completely my fault and its due to a lack of experience, (and being wet behind the ears) 

I have bent the down pipe assembly on one side where the down pipe actually bolts to the front of the engine (I have only managed to do this on 2 of the 4 rings which secure to the front of the engine) has anyone got any reasonable suggestions for trying to straighten these back out as the holes where the screws should go are now out of line by a few mm and it wont reattach to the front of the bike.

Ah the joys of being a young an in-experienced DIY mechanic. :'( any help as ever is greatly appreciated.

Ok  were taliking  exhaust STUDS",, were they sheard " and then you drilled them [ squint ]..  and now will not line up,?

In the above photo its the flat metal ring which fits onto the studs coming from the front of the engine - they haven't been tampered with other than having been over tightened and instead of  being flat like in the above photo they are in a slight U shape hence why they wont now go back onto the studs.

Ah the Collar"s  .  they are bent U shaped ,,  because -   the P/owner ?   or you, ?   was there new gaskets on top of old ,  hence  them being  forced to bend ,?

Plenty of heat and you should be able to bend them back

As above heat and GENTLY bending will straighten them, if you can find a BIG spring the same as you use to bend copper pipe and shove that down the end that will stop you kinking the pipe and causing more problems or if not then try a broom handle shaved down to fit inside and use the leverage from that to straighten them. Be careful use little effort cos you sure as shit can mess them right up if your to ham fisted.

Yes it's the collars that are bent have to try getting them hot and seeing if I can bend them back. It would seem as I have had them on the bike one side has been in the mount more than the other and as that's got tight and it's been turned on they must have bent to fit the strain that side was under. 

 

And it was so close to being back on the road.

Hi

When you fit stuff like pipes, or any item with multiple fasteners, it’s a good idea to only tighten the nuts/studs up by hand and to leave them loose so that the items can be jostled into place, then when tightening them fasten them in sequence slowly sharing the closing forces amongst each nut/stud as you reach the required torque,

If the pipe clamps are too bent extra twisting forces on the studs could cause damage so whilst doing this keep a close look as what is happening,

You may find that even with the collars being a bit bent they will still fit, after all they probably came off bent due to previous over tightening,

If you already do this then feel free to tell me to wind my neck in,

It would seem I've found the cause of the problem...shitty gaskets 

Looking at those I would imagine they've been overtightened as well, hence the bending of the clamps. Torque setting for the exhaust bolts on my 675 is 18nm I think. Yours would be something similar, I'm surprised there's thread left in the cylinder head

Yeah me to, as Finnerz said, that is the gorilla method of tightening up bolts.

I had this with a s/h XJ6 I bought and I used two vices one each side to bend them back,