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I was riding back from dropping a kid off at school and the bike just quit on me (in a construction zone, of course). I was able to fire it back up but it would quit again if RPMs dropped below 3k. I was luckily only a few blocks from home and coasted it most of the way.

After getting home, it wouldn't start at all.
I was expecting a fuel problem, but dealer mode shows a -C12 code, which is crankshaft position sensor, which is part of the Stator assembly, I believe.
I don't recall seeing the F1 light the first time it shut down, but I was also trying to get out of the construction zone and might not have noticed it.

The stator was replaced in June of last year under the recall.
Can anyone confirm that the crankcase position sensor (CKPR) is part of the stator assembly?
Has anyone else had this issue, and if so, do you have any advice?

Thanks,
ktech_stl






"EDITED the OP thread title"........
 

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Yes, the crankshaft position sensor is part of the stator assembly. Some aftermarket stator assemblies have you reuse this sensor, but not the factory.

I had the brand new stator assembly put into my 2012 for the recall. Wouldn't start. Changed back to the old stator/cps and it ran fine. So, they can and do go bad.

I would not trust running it at all. It may quit any time and never work again.
 

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What was the warranty on the replacement stator?
 

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FYI, C12 is the crankshaft position sensor not camshaft position sensor.

There is a two-wire connector on the right hand side of the bike, near the R/R, with green/white wires that go to the CPS. I would check to see if that connector is firmly seated because if it works loose then you'd get the symptoms you describe.
 
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Discussion Starter #5
Update: I ran through all the diagnostics on the Crankshaft Position Sensor (NOT CAMSHAFT, thanks!) in the service manual:
Voltage on White excitation wire: 1.85V
Continuity from connector to ECM: Pin 27 - White wire GOOD Pin 8 - G/BL wire GOOD
Coil Resistance: 180.7 OHMS

All the tests check out. The manual says the issue is now the ECM.

I don't get the C12 code until I have been cranking the engine for a few seconds.
Is there any way this is masking the real problem and I am chasing a ghost?

Does anyone have any ideas?

Thanks,
Ktech_Stl
 

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Static measures of resistance and continuity can be unreliable since things can change when it heats up or the motor is cranking. Intermittent electrical problems are very difficult to troubleshoot. Step number one would be to verify that the ground wire to the motor is not corroded or loose as that is a common cause of mysterious electrical problems.

Since the stator was serviced only about a year ago maybe the crankcase sensor has worked loose. See attached pic, sensor circled in red... so maybe those mounting bolts have worked loose and static test is fine but once you start cranking the sensor bounces around and loses the signal. If you are careful you might be able to pull the side case without damaging the gasket and take a peek (though you may want to have a gasket on hand just in case).

Its a long shot but you could call the dealership who did the work and see if they will check it under warranty.
 

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dmfdmf quote: "Intermittent electrical problems are very difficult to troubleshoot."
One of my old mentors told us.."There is no such thing as an intermittent problem. There is a problem that will show itself every time when certain conditions are met. Your job is to duplicate those conditions so that they can be diagnosed."
Words to live by.
If you have the conditions such as engine rpm, load, vehicle speed, ambient temperature, gear your in, any other pertinent info, you'll have a fighting chance of finding the cause of a problem.
My mantra, given to me from a techline manager of "Always look First where the human was LAST" also applies here.

dmf has it 100% correct here in his post and picture.

So you know, there is a test for any electronic control module. Test every single input and output to and from the ECM from both ends, powers, grounds, loads, all of it. It everything checks out, by process of elimination, it HAS to be the ECM. And there is no guarantee that a new part is a good part. "New" does not necessarily equal "Good".
 

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I would add that it is exceedingly rare for an ECU to fail.

My bike would crank all you wanted but never fire. Until I put the old stator/sensor combo back in. Done that twice to confirm I hadn't done something wrong.

There is an chance that the CPS is loose and no longer able to make a signal to the ECU. I would check that first.
 
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Discussion Starter #9
Thank you for all the input. I was able to test a few more things tonight:

I think I am getting fuel, I haven't done a fuel test, but the fact I don't get ANY firing tells me that is isn't a low pressure or low flow situation and it would be exceedingly rare for the Fuel supply to be cut off completely.

I am not getting spark (tested by the ultra-scientific method of removing the horizontal cylinder spark plug and grounding against a steel bolt in the cylinder head.)
I was able to get it to crank for a couple of 10-15 second crank cycles without the C12 error flagging, which is also exceedingly puzzling.

I am pretty confused. I will talk with the dealership again tomorrow. They have been feeding me ideas and the test process.

Still open for further thoughts and ideas of all of you that have more experience wrenching on these than I do.

Ktech_stl
 

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That is exactly how a failed signal from the Crankshaft Position Sensor will act.

Definitely need to pull the magneto cover and inspect the sensor and wiring. Could be the two fasteners are loose and allowed the sensor to fall away from the rotor in a way where it won't be able to pick up the points on the rotor. Would explain any intermittent running or running poorly then quitting. There could also be a pinched wire where the magneto cover and wire loom meet.
 

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There are other reports of dealer mechanics screwing up the replacement of stators under warantee and causing this problem. That would be my goto - undo that sidecover and check.
 
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