Port repair

[Lozza]

"Had it fall off be ground by the rear skirt get burnt and disappear out the exhaust"

And you may end up with an air leak and your motor may shit itself. Clean it well, Tig weld it and match it to your reed block. Bog is for plasterers

 Proving that old saying correct "Its better to be thought a fool than opening your mouth and removing the doubt".

[shelpi]

Ya have My attention

[Nebo]

    Jap cases have a very high percentage of Silicon. Forms as Black slag in the weld. Have to keep grinding it out. Very time consuming.

    Example early Honda XR and KX sump plugs. Stripped or Ripped out. Ask Gavin Cosway how hard they are to weld.  Must of Done Hundreds of them.

[Tomas]

"Had it fall off be ground by the rear skirt get burnt and disappear out the exhaust"

And you may end up with an air leak and your motor may shit itself. Clean it well, Tig weld it and match it to your reed block. Bog is for plasterers

 Proving that old saying correct "Its better to be thought a fool than opening your mouth and removing the doubt".

Have you read that somwhere dude? Nobody seem to take your idea of boging parts seriously Mr. I know everything hahaha ha

[shelpi]

    Jap cases have a very high percentage of Silicon. Forms as Black slag in the weld. Have to keep grinding it out. Very time consuming.

    Example early Honda XR and KX sump plugs. Stripped or Ripped out. Ask Gavin Cosway how hard they are to weld.  Must of Done Hundreds of them.

Yep Ive had the same problem! also the Suzuki t250 do the same, the trick is to get a weld run onto the parent metal then go back (after a clean ) and weld to the previous pass (weld) stop most of the porosity and drop out, with a lot less oxidisation
And yes there are guite a few additives in the old Jap castings to help it flow and get that nice smooth finish, Oh yer use the right series rod for the job and set for cleaning (we had fun working this stuff out lol)
oh yer heat the job right up to burn the oil out of the pours  before welding

[yamaico]

oh yer heat the job right up to burn the oil out of the pours  before welding

I always boil any engine parts that have been subjected to oil in a big drum, topping up with fresh water regularly until no more oil floats to the surface. Clean with acetone, S/S wire brush then a couple of dummy runs (no filler rod) with the weld width biased all the way to cleaning. Another hit with the wire brush, weld width back to normal, and good to go.

Oh yeah, and leave the Devcon on the shelf where it's supposed to be...

[shelpi]

oh yer heat the job right up to burn the oil out of the pours  before welding

I always boil any engine parts that have been subjected to oil in a big drum, topping up with fresh water regularly until no more oil floats to the surface. Clean with acetone, S/S wire brush then a couple of dummy runs (no filler rod) with the weld width biased all the way to cleaning. Another hit with the wire brush, weld width back to normal, and good to go.

Oh yeah, and leave the Devcon on the shelf where it's supposed to be...

I like the boil the bits, will definatley go down that path, oh and thanx for mentioning the acetone (forgot to mention that)
some cases be prepared to just go in and get that weld on the parent metal in one /the first pass, just so much inclusion and porosity, but get that first pass (weld) then keep welding off of that (like I said only some old covers ie Suzuki T250) cheers