I have a 2006 Ultra Classic. I brought it to a Power commander dyno center to get it tuned as it was running rich. We had to change the fuel filter but other than that all was well until the last stage of tuning being the 100% throttle. All was going well until a message came up that the Crank Position Sensor was not communicating or has failed. Right at that time significant oil blew out from around the sensor. I was there and saw the whole thing happen. The engine was shut down pretty quick. We pulled the sensor from the block and it looked like it had exploded. Almost all the plastic housing was gone and the copper coil housed inside was damaged. The plastic looked like it melted. The crank case was full of oil but I think that was because the oil returns were plugged with debris.
So now the engine will need a tear down end to end complete so it can be cleaned properly. We opened the cam chest and all is fine in there no damage but a lot of fine particle.

So what I would like to know is, does anyone have any idea what may have happed aside from some foreign matter getting in the crank side on the case.
The engine will be opened up later this week.

 

we cracked the case open and the only thing in it was the remains of the sensor. see the pictures. anyone have any ideas what happened.

 

My guess would be the oil over-heated and melted the sensor housing... that's what it looks like in your pictures. I've read of other accounts of this happening on a few Sportsters, which are also plagued with CKP failure, particularly the '04 to '06 years. Generally they just stop functioning partially or fully, but some do fail catastrophically like yours did. Don't know about the big twins, but Sportsters are also prone to wet-sumping during extended hi rpm runs, which may aggravate the situation. Oil blowing out from the sensor may be indicative of that!
Were cooling fans used during the dyno pulls?

 

Possibly the sensor was improperly installed. The principle of operation is that of a conductor cutting a magnetic field induces an electrical pulse.

.............. or excessive runout due to bearing wear/crank flex.

 

They are idiot proof as far as installation goes, there is only one way they can be installed. His pictures clearly show the plastic housing is melted, as in cooked... doubtful that was caused by bearing wear or crank flex. These are well known to be problematic in the early versions (there are B and C versions out since) A catastrophic failure like this is a little unusual though, and is collateral damage from some other issue. Here is a picture of the failed sensor from my Sportster... no visible damage, yet it doesn't work.

 

I have no help mate but that's hell bad luck.. hope you get her going again soon without any more problems

 

Catastrophic failure describes it pretty accurately. It would be interesting to know what the clearance is when they're installed. I find it difficult to believe that it melted though.

 

My broinlaw lost one while riding to Virginia City during Street Vibes.
He noticed oil blowing out while riding and stopped.The crank sensor failed.

Dont know what it looked like but it was replaced on the side of the road and then finished the ride with no problems.

Your's definitely got cooked and must have left debris in the engine.
Could it be because of improper cooling during the dyno?

 

yes 3 cooling fans were used. I suspected over heating but how do you really tell.

 

sensor was correctly install and that crank just came back from shop who aligned tuned and balanced the shaft to my piston weights. run out was less than 0,.001