Bike won't start--replaced Hall Sensor

My bike quit last week on a trip. Got towed to a m/c shop. We tested the spark leads, coil, and narrowed it down to the dreaded Hall Effect Sensor. New OEM sensor was installed and the bike ran great today after i picked it up until i got it home.

Here's what i did since picking up the bike (a few hours):

1. washed the bike
2. fitted a used sidestand switch (it was working properly).
3. TB synch

After i washed the bike two things happened:
1. water got into fuel filler neck
2. bike had stumbled idle; white smoke from exhaust (not gaskets, just had them done).
3. Bike kept stalling and then would not re-fire. It turns over but does not catch.

Question: Could it be a) water in the fuel; or b) sidestand switch is not right? I noticed that when i got the bike back, the brake light remained on all the time--short under tank?

mgordon said:

Oh, also, water is pooling around the fuel filler neck. Is it possible water got in the fuel and won't ignite, or more likely that water got in the ignition/kill switch wiring? 94 R1100RS

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Water in the filler neck means that either you have a clogged vent tube, or the shop hooked the vent tubes up wrong. The vent tube at the filler neck is supposed to go directly to the atmosphere beneath your right footpeg. The tube in the tank goes to the canister. Blow some compressed air up the vent tube from the bottom. Have your gas cap open and see if anything comes out. You might want to put a rag in the opening. If no air comes out, the hoses are probably switched.

update: have pulled the tank, drained it. New gaskets, fuel filter. No spark. Faulty Hall Sensor?

Towed it to a dealer. I wish i had been able to do this in the first place. An initial thought from the mechanic is that improper ignition timing by the installing shop hooped the HE sensor. I also know that the (non BMW) mechanic used an analog multimeter while doing the timing. Maybe that destroyed the sensor?

Bike won't start--Blown Hall Sensor

Here's the update: the bmw dealer plugged my bike into the diagnostic computer and the new HES is toast. I know that the shop that installed the sensor two days ago (non-bmw mechanic) put an analog VOM on it to try and do the ignition timing, and according to the info referred to in the Jan ON mag article, 40ma from an analog meter would kill the IC on the sensor. Also, the BMW mechanic told me that incorrect timing can also kill it.

A bit of a negotiation now to get the installing shop to cover the repair. The BMW shop which actually supplied them the HES won't warranty the part since they didn't install it.

Fun.

mgordon said:

Here's the update: the bmw dealer plugged my bike into the diagnostic computer and the new HES is toast. I know that the shop that installed the sensor two days ago (non-bmw mechanic) put an analog VOM on it to try and do the ignition timing, and according to the info referred to in the Jan ON mag article, 40ma from an analog meter would kill the IC on the sensor. Also, the BMW mechanic told me that incorrect timing can also kill it.

A bit of a negotiation now to get the installing shop to cover the repair. The BMW shop which actually supplied them the HES won't warranty the part since they didn't install it.

Fun.

Click to expand...

Good outcome - but I'd love to hear the explaination how the timing being off could damage a HES.. to me that's just bullpuckey.

Hi Don,

Thanks. I agree that the comment re: off-timing=blown sensor is questionable. Regardless, the sensor is blown. I just hope the original shop doesn't try and shirk responsibility.

Further update: first shop confirmed they did not put an analog meter on the HES. Also, I'm told that if that was the case the sensor would have failed immediately most likely. So, just to be sure the BMW shop is now testing my old HES to make sure it's not a fault with the Motronic. Regardless, because they confirmed that since the part was ordered and installed by another shop, and installed correctly, the part will be warrantied. Phew!

Question: could my having washed the bike pooched the brand new sensor? I don't see how, as when i pulled the alt. cover off there was no moisture there nore at the connector under the tank.