Which filler rod for Yamaha side case?

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I have been asked to repair a cracked engine side cover off a 1999 Yamaha R6 sport bike. The owner had previously repaired it using JB weld and then later decided to to see if I could weld it up. He ended up grinding the JB weld off which is why the cover looks the way it does.I typically only weld fresh new aluminum 6061 and so I always know what material I am working with. In the case of this engine cover I am unsure which filler rod to be using on it. I researched what I could but have come up short. I know earlier engine side covers were magnesium however I am certain this Yamaha case cover is some form of aluminum. I have read that Japanese bikes typically use a low grade aluminum however I really do not know what I'm dealing with.My plan is to grind a nice wide v-groove into the cracked section, clean, clean, and then clean some more, pre-heat the cover, and then TIG it up. Does anyone have any suggestions as to what filler would work?Thanks!Gordhttp://gordsgarage.wordpress.com/
Reply:Make sure it isn't mag.!ve always used 5356 on cast.DONT SANDBLAST IT!!Miller Dynasty 200DXMiller Spectrum 250DMiller Millermatic 200Bunch of old blue dinosaurs....
Reply:maybe make some way to bolt it down/secure it from warping as you weld it?Hobart EZ-Tig newbie.
Reply:Originally Posted by jontheturboguyMake sure it isn't mag.!ve always used 5356 on cast.DONT SANDBLAST IT!!
Reply:^^ Go sandblast some aluminium and then weld it. You're gonna get a mix of answers on the wire choice Gord, some of based on 'speshial ed' reasoning. While pretty much any ally welding wire will physically work silicon is the most commonly used primary alloying element in Al castings. That's why i usually reach for 4043 if the flavour of an Al casting is unkown. More detail on Al casting alloys here... http://www.keytometals.com/article30.htm
Reply:Or you can just tell me why?Torchmate 2x2 CNC with Flashcut CNC controlsHypertherm Powermax45 Esab ET220i Razorweld 195 MigRazorweld 200ac/dc TigTormach 770, Tormach xstechRazorweld, Vipercut/Vipermig, SSC Foot Pedal Dealer
Reply:sand blasting will drive the oxide your trying to remove into the metal along with bits of sand, you will end up with an extremely dirty weld if you can get a puddle to get rolling at all. grind that crack out with a carbide burr and clean up with a stainless wire brush and acetone. If its aluminum 4043 or 5356 are good choices, but there is a solid chance that it is mag as they were trying to cut weight on these engines. and easy test is to file up a small pile of dust and see if it will burn, if it sparkles it could be an aluminum/mag alloy which has been seen before, if it lights up hot and bright its mag, welds about the same as aluminum but you need to hold a closer arc
Reply:Obviously in this case there'll be a convienient pile of fillings from veeing out the crack but FWIW a drop of vinegar will react with mag alloys (acetic acid + mag = fizzing, bubbling and hydrogen gas) but not aluminium alloys
Reply:I've welded hundreds of broken aluminum and Magnesium cases and broken parts. The very worst thing someone can do is to weld something with Jb weld that they intend to have fixed right. You have to remove every tiny vestage of JB weld to be able to weld a contaminated part. One microscopic speck will foul your weld. I Used to charge double for anything with JBweld on it. If it is magnesium and you weld it with aliminum rod the weld will fall off, Or visaversa.  Mac
Reply:The right answer is to replace the cover. If a bike leaks oil, yer asking for an accident. I don't care how good a welder someone is, not worth the risk on a high perf motorcycle.
Reply:This should be a piece of cake...  just take your time and prep the metals nice.  Vee out the crack with a carbide burr, and weld both sides for full penetration.That Yamaha case looks a lot like this Honda one I weld repaired:http://weldingweb.com/vbb/showthread.php?t=45036I am agreeing with hotrodder, to use a silicon alloy (such as 4043) filler rod, to better match the likely parent alloy.  These are apparently die-cast aluminum alloys, which likely have high silicon content.As a second reason why 4043 would be a better choice than 5356, the high Magnesium percentage in 5356 is supposed to be avoided in applications that see elevated temperatures, in order to avoid stress corrosion cracking.  And, I'm betting that these motorcycle engine cover can get pretty warm.
Reply:Thanks guys for all the great suggestions. I followed recommendations and ground off some of the housing then took a torch to the filings, they didn't burn so I going to say that I am dealing with some form of aluminum. I think the game plan is as follows;-Smooth out the cover and try to ensure that I get rid of all the old JB weld-V groove the crack with a carbide cutter-Clean it, then clean it, then clean it some more (I won't sandblast)-Preheat it-Patch it up using some 4043 filler-Leak test itI'll let you guys know how it goesThanks jakeru for linking me your post, looks like I am dealing with the same thing.Thanks!Gordhttp://gordsgarage.wordpress.com/