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Case cracked at starter shaft


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So I picked this bike up for my wife to ride, previous owner said it was "punished", cleaned it up, changed all fluids, synced carbs and put 2 desert trips on it with excellent running... was adjusting the clutch and found the case cracked behind the stater shaft, I bet someone engaged the kicker while running or some shite.

 

In my mind this shouldnt warrant a new case, so I am just up in the air about splitting it, I think I can fix it without pulling the case, super short on time. I see 2 options.

 

1. TIG Weld

2. JB weld

 

I think TIG would be best, but can it take the heat is the only question?? I was thinking to minimize the heat to not even weld in the shaft hole where its broke, instead pre-cut a chunk of aluminum to fill in the hole underneath where the webbing is, just take a couple quick shots with the TIG and weld the chunk to the underside of the broken piece to just kind of hold it up. 

 

Or... do the same method with JB, shoot a ton of brake cleaner at it, drill a few shallows holes and scuff it for the JB to grab into, and wedge a chunk of steel or bolt up underneath to support the shaft hole, tape over with duct tape, and fill the entire cavity with JB.

 

Better ideas, thoughts??

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Anything other then a new case is just a temporary fix. Both methods you describe won't actually get rid of the Crack so it will continue to propagate from the sub surface parent metal through the filler material or the grain boundary between the two. I would also be willing to bet that there are Cracks that you can't see by eye. You could use a liquid penetrant technique to really see the full extent of the cracks.

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I am aware it may have other hairlines, but it appears to be completely broken off and isolated just to that area that was un-supported underneath - I wont make assumptions, but at the moment I am in the middle of 3 other bikes (favors on 2 of them) among 99 other projects. This bike wont get 25 hours this year, so I am going for the quick fix... hopefully a deal will come around for a set of cases later on.

 

My only question- can it take the TIG with the motor intact, or will it overheat seals or something??

 

I am thinking if I drop a short bead and let it cool for 15, then drop some more bead it shouldn't over heat??? I funneled some gas in behind it to flush out as much gear oil as possible, then blew it with compressor to clear out gas, hoping its cleared out enough not to ignite any oil.

 

Obviously a single kickback could destroy it even if it was brand new - so repaired or new I take close to the same risk.

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Shee cases are junk material to weld , but it can be done ? And I've done it before , usually I insist on a tear down for two reasons , cleaning and preheating . Clean is the #1 priority when tugging aluminum next is being able to preheat the case to limit heat fatigue on the metal . Someone can correct me if I'm wrong. Next I have seen tig if not preheated properly cause the surrounding area to become pourus and weak. Again I'm no expert on metals but I have done enouph shit to these shee motors to give an opinion. I know your not gonna take it apArt despite what I say just make sure whoever does it is qualified and for shits and giggles unplug your electronics, I've never had an issue on the shees but on other platforms I've seen the hi frequency cause some shit

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