Rather uncommon.
The sensor melts from the sealant side, not the back cup side.
Is there any possibility that a wobble is/was present at the cup/shaft.
Is the cam original factory cam?
Reason, there are a few scratches on the washer that holds cup.

 

Cow magnet
Plastic breather
Still need to clean out the chest


morning i opened the cm chest.....Inner cam bearing is gone.

Looks like most of the metal stayed in the cam chest, I am going thru oil pump tomorrow. Cam and the plastic breather are junk. No gears are broken and so far no keys are sheared off or any other parts are broke....I know some metal might be in the case.....
Pictures are coming

 

Ugh.... Bad do-do.

Many ways to attack this, but a few of them are going to be severe...

Personally, I'd just clean everything up as good as I could. Then clean it up again. Put it back together with a Torrington bearing, and run it.

If/when it blows up, I'd activate Plan B...

 

Those damn INA needle bearings...the achilles of the evo. Bummer, but on the positive side now you get to put the cam you want in.

BTW, what causes those to blow out like that, corrosion? Low oil/high heat at some point?

 

Well, so much for the lottery ticket.

Good job going in any anyway. At least you're at the bottom of things now.

 

My guess would be not enough rollers in the cage, and a weaker cage design, to adequately handle the stress. The OEM cam profile is extremely mild, so in a nod to the bean counters, The MoCo probably spec'd the cheapest bearing they could find that would get through the warranty period.

I pulled mine about a year after taking delivery of the bike (when it was out of warranty), and installed a Torrington along with the EV27 cam.

 

Sorry that this wasn't an easy fix. Harley owners are the only ones to put up with cheap parts and poor engineering, like the twin cam.

We all drank the marketing coolaid from the factory. A $5 bearing can cost a person hundreds of bucks. Don't know about you, but that just sucks.

Good luck with fix.

 

Took out what was left of the inner cam bearing case see picture.
Worn thru the bottom, pulled oil filter dumped out more metal.... haven't opened oil pump yet....I still had oil pressure when she stopped. Little rough on the bottom edge.
This cam out of the filter, looks like I'm panning for gold
Now this is some special metal....this is what left inside the filter.
Bottom of the old bearing.

 

Ugly.

That bearing had been going bad for some time. But with under 20,000 miles on the bike, that's really awful. I pulled mine around the 11,000 mile range, and it still looked new.

Did your bike have the OEM cam? Or did some knucklehead put in an aftermarket cam without swapping out the bearing?

 

All stock... "N" cam