Anyone fitted a CBR exhust (downpipe)?

[wiffers]

Bike (CBR600F '95) failed MOT on a rusty/blowing downpipe cos it's been stuck in garage

Garage said bolts probably rusted,and they wouldn't heat them up to remove. So I soaked in oil/WD40 for a week (on and off and heating it up). And tried. 3 came off easily. 1 had to be heated to 'cherry hot' 3 times, then came off too.

One of the middle ones is still intact and will need to be heated (labelled 'OK' but one sheared off labelled 'broken' - I will have a bit of stud sticking out, so will try and heat it and use mole grips to remove. But failing that, it would need to either be drilled (out of an aly head, with fadiator, forks, wheels, faitrings etc in the way), so an absolute fcuker of a job.

Anyway, I have some ideas/questions.

Firstly, does anyone know if the gaskets seal the pipes to the block flat (along point B), or on the tapered tubes (labelled A). Cos if A, I think that the seal would be tight enough with just 2 out of the 3 possible bolts, as all the plate (B) does is hold A tight to block, not for a seal. So I may be OK with 5 studs.

1. So, do gaskets seal B to block, or go around A?

Also, I may try and be clever and make another plate (washer) which goes over the OK central bolt, and tightens over the broken one, pulling it in a bit. If the gaskets seal B to the block, would they be OK with a missing bolt, or with this little bit of force. Obviously I'd gunk the area up.

So if gaskets are flat and seal B to the block, will the exhaust tubes hold on missing the central bolts (on one side), or would they blow (even with gunk)?

Finally, has anoyone any other tips of getting this working? Or, failing that, know anyone in the Salisbury area who will drill this out?

Thanks

http://www.webbedfeetuk.com/Crap/exhaust.jpg

[Guest]

get a stud extractor and a new stud..

http://www.mandp.co.uk/productinfo/5472 ... Hand-Tools

you may get away with an allen bolt instead of a new stud..

the gaskets sit inside off a lip on the engine then the exhaust butts up against it.. just try it and see...

[Voodoo]

Another way to remove a stud (if its long enough) is to use two nuts. Screw the first nut on, then the second nut up to the first. Then use a C-spanner to unscrew the first nut.

[wiffers]

Walney. Gonna be a bugger to extract. Only got a bit of thread, rusted in, only 7mm steel in an ally block, very hard to get at (not like it's on my bench), plus it's a 7mm thread - grrrrrrrrr

I think making it red hot, mole grips and asbestos fingers will be the best way.

And an allen bolt would be fine, IF I can get the old one out. A new bolt is only £3.50, not an issue, it's just getting the old one.

Voodoo - nowhere near long enough mate, I'll have around 4mm to play with I should imagine. i.e. the thichness of B

[Guest]

can you weld/have access to a welder..?

slip a nut onto the thread, and weld it on, then undo like a bolt..

or slip a nut on, hammer the excess over the nut then undo.. the nut will lock against the excess and should undo as its the path of least resistance..

[wiffers]

I have access to an arc welder, but the nut will be a bast*rd to get at, and not sure my welding is that good. But superb idea - will have a think

Rounding the edge with a hammer also good, but may be difficult as only have a few mm to play with.

Another idea I have, it turn a nut in a lathe, and make the hole in plate B slightly bigger, to make something like this:

http://www.webbedfeetuk.com/Crap/exhaust2.jpg

Where original nut (pink) has been turned down on bottom half. Exhaust flange (blue) has been drilled further. Stud (green) is broken off flush to top of exhaust flange, but uses bottom thread of nut. Engine block on orange.

Could try that, put loads of gunk between flange and block, and if it doesn't work try the welding idea.

Cos once I try welding idea I can go back to this one as easily.

What you think?

Thanks for help

[wiffers]

Did it the way indicated in last pic. Seems to work a treat

MOT Thu