Welding a cracked case.

freddy

find a post by 'lineweaver' and "PM" him direct. he's revving up for daytona speedweek so he's a bit busy right now.

Taffy

Most all rough cast cases (any form of rough sand casting...white or hard green sand) are cast from 356 aluminum alloy and then heatreated to -T6 hardness. So, the final complete casting designation for 99% of all rough cast cases is 356-T6 (Note: the "T6" is the heat-treat designation, NOT the alloy designation as most people think). You can easily weld this alloy with 4043 rod, BUT make absolutely sure you preheat the cases to approx 300 to 350ºF in an oven BEFORE welding (should only take 30 min on "bake"). This will prevent warping during welding, but is not so high a temperature nor length of heat duration as to hurt the original -T6 heat-treating of the cases (but the alloy WILL BE annealed wherever your weld bead is). Just make ABSOLUTELY SURE that the cases are completely free and clean of ALL oil residue before baking. Use carb or brake cleaner to clean the cases first. If not clean of ALL oil residue, the weld bead WILL BE contaminated and weakened (and possibly porous....with oil/pressure leaks).

Pressure die cast Jap cases are usually a slightly different alloy for use in their injection (pressure) molding process, but the above repair process and rod selection are still the same.

Freddy said:

Hi,
I have 01 berg with a cracked case(close encounter with a rock). Does anyone know the series of aluminum used in the case castings?

Click to expand...

Hi Freddy,
Main engine case, clutch or ignition cover?

If the main case assembly is indeed the damaged component is it such damage that reduces the structural integrity or simply leaks oil?

If it is not structural may I suggest an interim repair using a patch such as JB Weld, etc. The weld repair can then be performed another time when engine disassembly is warranted.

If welding is the only and / or preferred method Rustie has outlined the proper protocol.
.
Preparing the damaged area (getting it truly clean) will prove to be your primary challenge.

Best Regards,
Dale

Ps
Should you decide to weld with the engine intact be certain to remove the ignition module prior to doing so.

:!: It should go without saying, but if you are going to weld on a bike, also make sure whatever is under it (eg fuel from out of the carb onto a piece of carpet!) can't burn. Coming back from lunch to find your bike on fire ain't good.