Terrified of What I Found - Please lend advice

[JP50515]

Alright guys I'm slightly scared of what I found. I cannot tell if this is a crack or just an imperfection in the aluminum casting but it is way too close to the edge for comfort. This is located directly above my stator right above that top bolt holding in the whole side cover.

What do you guys think of that and is there anyway to fill is before it becomes catastrophic if it is a crack?

I've heard taking die grinder, and basically doing to it what they to do your teeth with fillings but with JB weld.

 

[jd750ace]

First, sand it flush and make sure it is, in fact cracked. If it is, I would not attempt to repair it there. It's on it's way over to the base of your cylinder, from what I can tell, and JB Weld ain't gonna stop that. You might send that pic to someone who welds aluminum. I imagine a 4043 filler rod would work on the case (works for most cast and forged aluminum), but I don't think I'd run it again without welding it, if it's cracked, and it certainly looks to be a fatigue crack.

 

[gggGary]

No worries they ALL look like that, it's just how they were cast from the factory. Guess the number one reason Yamaha paints the crankcase? ( I think they paint the inside also)

Yup to keep the oil in.

 

[XSLeo]

Yes, just a minor flaw in the casting, if you look around you will prbably find more.
Leo

 

[JP50515]

How can you tell if it is in fact a crack though?

 

[XSLeo]

See post #2.
Leo

 

[JP50515]

so sand it? If it doesn't disappear its a crack kind of thing?

 

[JP50515]

Here it is after about 10 minutes of light sanding. I'm not exactly sure how long to sand this thing before making a decision.

What do you think?

 

[gggGary]

What I said above. The molten aluminum is poured into a casting it cools hardens and CONTRACTS that has the surface skim on the casting wrinkle. If it hasn't leaked it's not a crack. THAT is not a crack. I went and looked at 6 XS650 engines just now about half had lots of "wrinkles" like that some had fewer, one or two looked pretty nice. You need to find something better to worry about.

 

[jd750ace]

It's a flaw, as Gary said. Couldn't be sure without standing there. Sorry for any panic I caused.

 

[PetesPonies]

It looked worse before the sanding I agree. Fortunately doesn't seem to be a problem. Fissures in castings can indeed turn into problematic cracks.

 

[ReycleBill]

If it were mine I'd sand it smooth and clear coat it. As a matter of fact, that's how I fixed all the "cracks" in mine. But yes, there was a bit of concern when I first found them.

 

[gggGary]

Satin silver matches the factory case paint nicely.

 

[JP50515]

well in that case I'll leave it be. Ha was a bit concerned. Just finished the build and then found that like wtf

 

[angus67]

Satin silver matches the factory case paint nicely.

what maker of that satin silver? They all have their own twist on sheens, and such.
Some manus. cant even match their own mixes.

 

[gggGary]

I dunno, for case paint any satin silver looks a lot better than the original manky yellowed flaking silver. more often than not I spray into the cap and use a brush for touch up. to my old eyes it ends up looking great....

This was a barn find bike, polish the aluminum, brush touch up the paint and it's fairly presentable.

It's a hardtail bobber now but he didn't touch the engine.