Hub cracks?

I discovered a small, two-inch long raised area on the bottom of the hub months back that I thought might be a harmless fault in the metal. However, more have been showing up. It seems they are surface cracks and don't leak any oil. There are more than can be seen in the pictures running along the bottom of the hub. In addition to the longitudinal cracks running along the bottom, there are two vertical ones on the small raised area. The oil is fine and no evidence of stress (metal flakes) inside. Anyone else see anything like this (I have an '08)?

My '08 has the same thing. I noticed it a couple weeks ago when checking the final drive oil level. Not sure what to make of it yet.

Could this be a ridge created by dirt accumulating on the "edge" of a fluid (or grease) spreading across the part?

If this were the case, I think simply rubbing on it would tell the tale.

I'm guessing you guys have already checked for something as mundane as this, but figured I'd suggest it in case...

I haven't seen this before -

It looks a lot like poor prep work for the powdercoat.

Mine looks the same...no worries.

Saying that it is a crack is a little premature. I work in the machine shop in my company and castings do not just develop cracks out of nothing. These parts have been checked and double checked by Yamaha and the only way to know for sure you have a crack is with a NDI test called Die Penetrate type inspections. If you think it is cracked than I would remove it, take it to someone to have it checked and than get Yamaha to replace it if it is defective. Other wise please do not start the world is falling stuff.

By the way a crack in the casting would be very dangerous to ride in.

Be safe.

DJB said:

Saying that it is a crack is a little premature. I work in the machine shop in my company and castings do not just develop cracks out of nothing. These parts have been checked and double checked by Yamaha and the only way to know for sure you have a crack is with a NDI test called Die Penetrate type inspections. If you think it is cracked than I would remove it, take it to someone to have it checked and than get Yamaha to replace it if it is defective. Other wise please do not start the world is falling stuff. By the way a crack in the casting would be very dangerous to ride in.

Be safe.

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Geez I didn't think anyone was doing that. Karmak said they "looked like surface cracks" and on my final drive they also look that way. I surmise it's probably just the powdercoat like Kaitsdad said, but they have a hard ridge and could certainly be mistaken as cracks. When you first see them it can be quite unsettling.

He was just asking a question and describing what he saw.

It would be quite odd for a crack to develop that did not go all the way through the metal.

Additionally, it would be odd to feel a raised surface unless some pressure developed that

forced the metal outward causing the cracks that would most likely extend all the way through

the metal.

Try this..

take some simple green and spray the area. Let sit 1-2 minutes then hose off. Is it gone? Most likely

dirt settling into a casting or powdercoat flaw.

The cracks are raised areas in the powdwer coat probably. They dont wash away....

DJB said:

Saying that it is a crack is a little premature. I work in the machine shop in my company and castings do not just develop cracks out of nothing. These parts have been checked and double checked by Yamaha and the only way to know for sure you have a crack is with a NDI test called Die Penetrate type inspections. If you think it is cracked than I would remove it, take it to someone to have it checked and than get Yamaha to replace it if it is defective. Other wise please do not start the world is falling stuff.
By the way a crack in the casting would be very dangerous to ride in.

Be safe.

Click to expand...

DJB-Lighten up, read the post. I said "appeared to be surface cracks. That means in the surface material, not through the whole hub. No one implied the sky is falling except you. The rest of your advice was good advice.

It is always best to be safe than sorry and whatever is causing this certainly does not appear to be isolated and certainly shouldn't be happening.

Yes, Yamaha checks and double checks-just as they must have for all the "tickers" we discovered. I'll trust in my observations and the observations of all the guys and gals on the Board and then we'll see if there is any need to look further.

You may or may not have had an '05 or earlier, but those of us that did saw first hand how Yamaha's quality control failed and how they never formally "fessed up." It was the "question-answer-discovery" process that began predominantly on Boards like this that armed many people with the information necessary to get Yamaha to right a wrong.

The bottom line is that no matter how far the cracks extend-to the surface or beyond-they shouldn't be happening at all.

kaitsdad said:

I haven't seen this before -
It looks a lot like poor prep work for the powdercoat.

Click to expand...

I'm guessing that also. There is no significant internal pressure except oil whirling around, so the casting wouldn't fail due to any kind of stress.

In any case it is aggravating-they have definitely increased and who wants a hub or swing arm covered with spider web cracks!

Lets not forget how much aluminum expands and contracts, I would say that is going to be the primary culprit.

Karmak said:

kaitsdad said:

I haven't seen this before -
It looks a lot like poor prep work for the powdercoat.

Click to expand...

I'm guessing that also. There is no significant internal pressure except oil whirling around, so the casting wouldn't fail due to any kind of stress.

In any case it is aggravating-they have definitely increased and who wants a hub or swing arm covered with spider web cracks!

Click to expand...

+1, I've got them too. Looks like the powder coat or whatever they plate this with

You could always do a Dye-Penatrant inspection to see if they are infact cracks. I've noticed a little pitting in my '05 FJR, but no cracks.

Hey these things arent BMWs LOL

Jeff Q said:

Hey these things arent BMWs LOL

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I have to admit-that went through my mind at first!!! Rather have screwed up powder coating and surface cracks than catastrophic shaft drive failure!!!

I have seen a few posts about the paint cracking and Yamaha replacing the unit. That hub gets pretty hot but so does the motor. I remember seeing the posts listing multiple years that this has been an issue.

I'll see if I can find a few threads on it.

Jeff Q said:

The cracks are raised areas in the powdwer coat probably. They dont wash away....

Click to expand...

But the dirt will, making the cracks basically disappear.