Cracked casting around bearing journals

[pereiracycles]

Hey all,

I built this motor in 2000 and have been riding it since. All was well until the last few weeks when the motor got noisier and noisier. I knew it was getting tired and would need a rebuild anyway, so I kept riding it until it pretty much quit. I know, not the smartest, but anyhow...

I've got the engine out and have been inspecting and cleaning for the last week and noticed some missing chunks of the upper engine case casting around the main bearing journals. It looks like some of the case casting around the steel journals has cracked away:

Has anyone seen this before? I don't see any cracks extending into the case above these spots. Should I replace the crankcase or do you think it is ok?

The engine failed because one of the conrod/crank bearings got chewed up. Metal everywhere, but it is cleaning up ok so far. I'll be replacing the crank with one of Hugh's and will likely do a 750 re-sleeve.

Thanks,
Tony

 

[xjwmx]

It looks like some of the case casting around the steel journals has cracked away:

Has anyone seen this before?

Can't see it. I must need glasses.

I'll be replacing the crank with one of Hugh's

Aren't they $10,000 and made of platinum? I'd opt for a real man's oem crank myself. 65 bucks on ebay.

 

[pereiracycles]

Can't see it. I must need glasses.


Aren't they $10,000 and made of platinum? I'd opt for a real man's oem crank myself. 65 bucks on ebay.

Yes, everyone knows that platinum is the best.

Here's the pic

 

[xjwmx]

I wouldn't put a platinum crank in that shit.

 

[Downeaster]

Personally, I wouldn't trust those bearing saddles, ESPECIALLY if you're going to a 750 kit.

Folks with more actual knowledge will check in tho.

 

[member3480]

Need parts I got cranks ,Cams,Cases and I have a good bottom end together

 

[gggGary]

Just an opinion but I'd find a different engine to build from crank and all. Typical "used to run" lump can be found for $100

 

[TwoManyXS1Bs]

I see signs of "fretting wear" in those bearing seats. Would be nice to see the matching surfaces of the crank bearings, for confirmation.

If it is, the bearing seats aren't fully clamping the bearings. Probably from high revs. The case would be no good...

 

[YamadudeXS650C]

I'm waiting for someone to suggest using a little JB Weld on those bearing journals.

Just kidding. I agree, the cases are toast, IMHO.

 

[pereiracycles]

Thanks, everyone. That's pretty much what I thought. May be the cause of the engine failure.
So yes, I'm in the market for a new set of cases @DADDYGCYCLES Got a price? DM me if you'd prefer.

 

[xjwmx]

I see signs of "fretting wear" in those bearing seats.

Is that the patch to the right of the locating pin in the second one?

What causes the difference in color between the edges and the inner part?

 

[kshansen]

What causes the difference in color between the edges and the inner part?
View attachment 103965

The inner part that is darker is a cast iron insert molded into the case then bored out to fit the bearings.