Spark erosion

[Laverda Dave]

I've made a real schoolboy error  with the CB250RS engine and now I need a pin spark eroded out. Does anyone know of anyone who can offer this service? All the company's that advertise are only interested in mass production work and not one-off's. Happy to send the part (it's the rocker cover) anywhere as it's only small.

[Trigger]

Show a pic of what needs to come out

[Tomb]

Will a slide hammer not weld to it?

[Laverda Dave]

Here's the offending pin, it's 5mm diameter x 28mm length (although shorter by 8mm now as a bit broke off trying to remove it using heat, dremmel, pliers etc.
I can't believe I put the pin back but forgot to check the spindle at the other end was in alignment with the bolt hole.....it wasn't and I only realised when I went to refit the rocker cover! I shouldn't have been working in a cold garage when I wasn't feeling well myself!!!

[Laverda Dave]

Its the pin on the right, the one on the left is fine!

[AshimotoK0]

Will a slide hammer not weld to it?

+1 that's what I was thinking ..you will get loads of localised heat too. When I did my 750K0 stud removal someone told me to smear soap on the alloy and if it goes brown then you are overdoing the heat.

[Trigger]

You don't need a spark eroder on that, just weld a 8.8 bolt to it and draw it out. Or drill a hole dead centre and smack a torx bit and turn it out.

[Rob62]

I think he tried all that on a previous thread.... the pin is pot-hard. Looks like a strip down and off to a specialist toolmaker / precision engineer or the like, or failing that a replacement part. 

[AshimotoK0]

I think he tried all that on a previous thread.... the pin is pot-hard. Looks like a strip down and off to a specialist toolmaker / precision engineer or the like, or failing that a replacement part. 

I agree on trying to drill but I would have thought you could TIG weld to the pin...not tried it myself though so could be wrong

[K2-K6]

StudLever Dent Pulling Tool: http://youtu.be/RfsonLnIJLM

What about a car body repair shop that may have kit similar to the above to get a stud welded to it?

[Rob62]

I think he tried all that on a previous thread.... the pin is pot-hard. Looks like a strip down and off to a specialist toolmaker / precision engineer or the like, or failing that a replacement part. 

I agree on trying to drill but I would have thought you could TIG weld to the pin...not tried it myself though so could be wrong

Worth a try i guess

[70sHonda]

I don't know if he'd work on a Honda, but Pete Lovell of Pete Lovell Developments does smaller jobs using spark erosion. He's a long standing Norton man but it might be worth a try if you get really stuck. 

[Laverda Dave]

Thanks for all the help and replies everyone. I had this problem before and tried everything mentioned then (and so did Huw who's a newbie on here, he welded a stud on and it broke. I tried the drill but the pin is so hard it didn't touch it. Thanks for the tip about Pete Lovell, I'll give him a try. The only way to get this out will be by spark erosion.

[AshimotoK0]

I had two of the short cylinder head studs snap off slightly below the surface on my 750K0 ...I tried various attempts at welding a nut onto it (I even removed all traces of BZP with acid and then bead blasting the nut) but the nut kept breaking off. Then I watched a TV car resto programme where the guy welded a blob onto the top of a broken stud  and kept building it up to a quite large unsightly blob ...then, whilst still really hot, he removed the stud with Mole grips...I have since tried this method on  cylinder studs and snapped off brake fittings and it worked every time. The only thing I am unsure of as a novice welder is how weld will 'take' to a hardened pin.

[royhall]

A hardened pin will be fairly high carbon. Will weld okay but may become brittle and snap off.