Advise for repairing a cracked engine casing

[chrisjpartrid...]

I have a 2008 Sukida 125 - basically a copy of a Suzuki GN125 (generic Honda/Suzuki 125 air cooled engine clone) with an oil leak.

Today I have removed the engine, cleaned it to near-perfection and hung it off the ground (using a rope, a ladder and a spade!) and filled it with flushing oil.
After not much time I found there to be a hairline crack in one of the main engine casings near one of the mounting holes. The crack is only about a quarter inch long and took ages to find but is enough to drain the sump in a day.

There are a number of options but I can't work out which is the better...

I have a MIG welder so I could buy some aluminium wire (I assume it's an alloy casing!) and argon, but that's £30 spent plus I've never wleded alloy before so would worry about cocking it up.

I've considered epoxy (either Arldite or putty) but would this work/last?

Other options are things like JB weld or lumiweld but but I'd like to know if either would hold oil?!

The bike is faultless aside from this and before anyone asks, when the leak became apparent it was not allowed to run dry.
It's only done 2,000 miles and the over all finish on the bike is a lot better that some of the Chinese stuff I've seen in the past - shame they're still not quite there yet though.[/url]

[at106]

The best option would be finding someone local or an engineering firm who can TIG weld it, this may also be cheaper.

JB weld and lumiweld will also work. But i dont think JB weld is really a permanent solution and whilst it's all apart and cleaned up you may aswell do it properly.

I've used lumiweld before and i found it very difficult to use, and it also didnt hold oil that well.

[steven_191]

I use jb weld before and it was pretty good. I didn't have it contact with oil though but was easy to apply and set well. It survuved powder coating.

I would have someone else weld it. If its cheap alloy cast material there's normally so much crap in there the weld becomes hard to stick. Let a pro deal with it otherwise you may end up buying a new casing. (Although that may be a good alternative)

[jamesrs250]

i used quik steel on my drz 400 when i dropped it and it had a crack in the engine side casing..and i used it luke that for 200 miles..then bought a new one...i reckon it would of lasted permently

[Pete.]

One has to wonder why it cracked in the first place. Some of the Chinese clone bikes have very poor alloy and are prone to breaking lugs etc but it could simply be that the mounting bolt has become loose causing unwanted movement and vibration.

For get MIG welding it. You'll end up with a soggy molten puddle of metal and a hole in the casing the size of all outside.

Resin repairs like JB Weld arnen't structural so if it's cracked near a mount there's going to be flex - not likely to hold up well.

I would favour TIG welding also. I've had several rapairs done in cases and they ahve all been perfectly successful. If you did find it a little porous after welding which can happen if it's hard to get rid of impregnated oil.
____________________
a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good