welding motorcycle cylinder heads

[mechanical music]

is it possible to weld an aluminium cylinder head with a sip migmate 130, or is it way to small

 

[123hotchef]

Is it cracked

 

[mechanical music]

hi, no, its just to weld where the exhaust studs screw in

 

[Shox Dr]

In a word. NO

Not enough AMPs
Wrong type of Gas.

 

[merryman]

If the studs have pulled out, get it "hellicoiled" Getting a kit and doing it yourself would be cheaper than buying aluminium wire and the special gas mix for aluminium. Far less likely to go wrong as well. However, for a one off, either a motorcycle or car repair shop could probably do it for less than the thread insert kit.

 

[mechanical music]

one of the posts was damaged and some was drilled out wonky and messed up, i paid a pro to repair 2 stud posts, apparently he had to grind the whole posts off and built them back up with tig and charged me £40, so thought i would rather try to do any others myself if poss, also wouldnt mind having a go of alloy welding on a scrap head, thanks for your replies

 

[OJCar]

If you have a scrap head why not give it a try?
You could then post some photos of your attempts on here and the experienced can offer advise on how to improve.

 

[Fazerruss]

I wouldn't touch any engine cases at all with a MIG, it will just make a mess and more work to repair it properly.
Aluminum engine cases can be a can of worms depending on the marque. A 200 amp ACDC TIG is the minimum you want to do these kinds of repairs. It can take a few attempts to get a clean weld pool before adding any filler wire so this rules out MIG unless you want a weld resembling coal.
£40 is cheap to repair that so go back to him. When you factor in the time, materials and machining afterwards that's a good deal.

 

[Fazerruss]

Here are some horrors I've put right after someone else had a go......

 

[mechanical music]

Here are some horrors I've put right after someone else had a go......

View attachment 371878View attachment 371879

point taken, your pics show what looks like a professional repair, what i paid a blacksmith to do came back with damage that wasnt there as the new post have been ground so rough that they now have dips each side and the posts dont even look wide enough compared to original, so ime not pleased at all, thanks for your advise

 

[mechanical music]

If you have a scrap head why not give it a try?
You could then post some photos of your attempts on here and the experienced can offer advise on how to improve.

i dont have the correct wire/gas yet, but ive just been told the amps are way too low so not worth trying unless i win the lotto and buy a tig etc, thanks

 

[Fazerruss]

point taken, your pics show what looks like a professional repair, what i paid a blacksmith to do came back with damage that wasnt there as the new post have been ground so rough that they now have dips each side and the posts dont even look wide enough compared to original, so ime not pleased at all, thanks for your advise

To do it right the flange needs milling so the gasket faces are flat. It sounds like yours was done with an angle grinder which won't give the tolerances required.
This one had similar problems. Once the area is built up I then mill the flanges back to spec.

 

[mechanical music]

 

[mechanical music]

my initial quote was £40 for all 8 post/ stud holes to be filled slightly above the top so i could grind them down myself to save paying for that part, then it turned out i only needed 2 doing, and he still wanted £40 and ground them like this, ime drilling and tapping them myself....hopefully

 

[Fazerruss]

my initial quote was £40 for all 8 post/ stud holes to be filled slightly above the top so i could grind them down myself to save paying for that part, then it turned out i only needed 2 doing, and he still wanted £40 and ground them like this, ime drilling and tapping them myself....hopefully

To be honest all that needs doing again completely or it will just fail.
For a start the head is absolutely filthy and the weld has porosity down the side of the post so it's compromised.
The gasket seat is also butchered so it needs building up and re boring.
Once you drill and tap the holes I'd be surprised if there isn't voids in the thread.

 

[stuvy]

What are the heads from?

It’s a machine shop job but if your a skilled chap with a decent pillar drill you could do it at home

 

[mechanical music]

To be honest all that needs doing again completely or it will just fail.
For a start the head is absolutely filthy and the weld has porosity down the side of the post so it's compromised.
The gasket seat is also butchered so it needs building up and re boring.
Once you drill and tap the holes I'd be surprised if there isn't voids in the thread.

i totally thought the same thing, wasnt sure if it was just me expecting too much, its a head i recently bought off ebay for a bike project ime rebuilding/restoring, i paid too much for the bike as ive had to weld a piece in the frame as it was badly rotted, only to pay for more damage, ile be blasting the head and repainting everything, but might get the head rewelded, ime making a template for drilling the exhaust stud holes square before tapping them

 

[mechanical music]

What are the heads from?

It’s a machine shop job but if your a skilled chap with a decent pillar drill you could do it at home

its off a yamaha fzs 600 mk1, ime not too bad in general, but only got a small piller drill that takes a handheld drill, ive nearly finished making the drill template

 

[mechanical music]

To do it right the flange needs milling so the gasket faces are flat. It sounds like yours was done with an angle grinder which won't give the tolerances required.
This one had similar problems. Once the area is built up I then mill the flanges back to spec.View attachment 371882

any suggestions on the best way to degrease it before i have it rewelded, ive got a home made vapour blast cabinet with fine glass beads but dont want to contaminate it until ive cleaned the head

 

[Fazerruss]

any suggestions on the best way to degrease it before i have it rewelded, ive got a home made vapour blast cabinet with fine glass beads but dont want to contaminate it until ive cleaned the head

Start with good old petrol then some water soluble degreaser. Just before welding clean the immediate area with acetone and a wire brush