tricky job Earthing recomendations

[600rob]

i want to use this technique to remove a broken exhaust stud in my motorcycle engine

However unlike the video, the engine, along with the broken bolt is still in the bike!

There is about 25mm of the broken M7 bolt sticking out of the engine block.

Is there any way that i can get a decent earth on the bolt that will allow me to weld a nut on to the bolt.

The weld doesn't have to be pretty ( just as well because im a beginner),
Is just required to enable me to remove the exhaust stud.

Any advice welcome

Cheers

Rob

 

[wyn]

I would hold the nut in the earth clamp.

 

[rikrobson]

put the nut on the stud then the clamp on the nut

 

[600rob]

Cheers for the replies

@mrfuzzy

would something like this be suitable:
http://www.ebay.co.uk/itm/MMA-29-9-...865?pt=LH_DefaultDomain_3&hash=item58c3bb6761

 

[AndersK]

A piece of copper wire can be useful if earthing is difficult, or if the weight of the clamp can disturb tacking

 

[dobbslc]

Don't forget to unplug your cdi / power commander and the battery first.

 

[wristpin]

If there's room it's a lot easier to weld a washer to the broken stud and then weld round the outside of the nut to the washer, leaving enough clear for the spanner of course!

 

[Bill Edwards]

There is about 25mm of the broken M7 bolt sticking out of the engine block.

With that much stickout, can't you just get something to grip directly onto it, like decent vice grips?

If you're wanting to use weld for the heat, can you use a small blowtorch on the part instead?

M7 is pretty small/thin, use the smallest rod you have got and you won't want many amps or you'll end up melting the end off.

 

[600rob]

With that much stickout, can't you just get something to grip directly onto it, like decent vice grips?

If you're wanting to use weld for the heat, can you use a small blowtorch on the part instead?

M7 is pretty small/thin, use the smallest rod you have got and you won't want many amps or you'll end up melting the end off.

Tried the mole grips and the blow torch but i cant get it to move.

Also tried putting 2 half nuts together on the remaining thread to try and undo the bolt but the thread was too corroded.

Ill give this welding method a go and see if it works.


@dobbslc
cheers for the reminder.... i would have just done all of this with the battery/cdi connected!

 

[dobbslc]

What bike is it?
7mm sounds an odd size.

 

[Wendelspanswick]

What bike is it?
7mm sounds an odd size.

7mm used to be a common size on Japanese cars and bikes.

 

[600rob]

What bike is it?
7mm sounds an odd size.

It sure is.

Honda have a habit of using 'special' sized nuts bolts and fasteners

They then charge extortionate amounts when you need to replace them

 

[normspanners]

I generally use a pair of long nosed vice grips to clamp nut and put the earth on the back of the grips

 

[dobbslc]

Arrgghhhh bloody Honda!
You should have bought a Yamaha!

 

[Bsmith]

If space is too restricted for the earth clamp, you could put a piece of like 10mm round in the earth clamp then tack weld it to the nut. Just break it off when finished welding the nut to broken stud.

 

[The_Yellow_Ardvark]

This is how I used to remove broken exhaust studs etc from the Norton’s I used to rebuild.

• Clean up the stud as best you can.
  
  
• Use a decent stud remover on it. Try to tighten the stud a bit to crack it. Don’t use to much force as a broken stud is a pain.
  
  
• If there is any thread left force on a nut, doesn’t have to be the right thread or size, as long as you can get it to wind down a bit
  
  
• Weld the nut to the stud, looks are not important, strength is. The earth clamp has to be as near to the stud as possible. When space was tight I would wind some scrap cable onto the stud and clamp that.
  
  
• Try to remove the stud. Again by tightening a bit before undoing. When the stud is hot from the welding get some decent penetrating fluids onto it.
  
  
• That used to do the trick most of the time.
  

If the stud does break there are some good drill out kits on the markets, but make sure you get some decent sharp new drill bits.


Hope this helps.


7mm is a odd size, but as all ready mentioned found on Jap bikes and cars. But also on VW Polo and on Vauxhall Cavalier's and Astra to hold the clutch plate on, 7mm =to 11m spanner/socket.