[BRADEY]

Could anyone explain the function of the Crank Position sensor and its functions on the C5. On a ECU remapping schedule recently at my dealership, this sensor was found to be giving an error on my bike. Cheers.

[Arizoni]

That sensor is reading the pulses of the magnets on the alternator rotor to determine where the crankshaft is relative to top dead center of the pistons movements.

The computer uses this information to determine the amount of advance that is needed for the ignition timing and when to tell the fuel injection to inject a squirt of fuel into the inlet.

The engines speed and crank position plus, the oil temperature, the atmospheric pressure, O2 sensor reading and throttle position also determine where on the computer map the engine is so it can set the spark advance and fuel injection to the proper settings.

I tend to get carried away sometimes so simply put the Crank Position sensor tells the computer what the engine speed and timing is so it can meter the fuel and trigger the spark for the best running condition at any given time.

[BRADEY]

That was a wonderful explanation Arizoni. Many thanks.
I was wondering why the bike was stuttering so much in stop go traffic.
After the remap I was giving all credit to RE for resolving this issue. However it seems that it was actually the correct functioning of CP Sensor that did the trick..........so the first map was not that "Bad"  but I was fore warned by the Engineer that he will not be able restore the earlier map..............damn, I'll miss its raw power, as the new map gives the bike more milder manners.

[barenekd]

Usually a failing crank sensor, will start cutting out and quitting when it gets hot. The bike will restart and run after it cools off a bit, the quit again as it gets hot. I've had several failures from this little item on Triumphs. And they can quit on the most inconvenient spots, like the HOV lane on a freeway!  Fortunately most Enfields don't run there, so that problem is minimized!
Bare

[Arizoni]

BRADEY:  Sorry to hear the new map detunes the engine.  I hadn't heard that before.

Living in the USA, I'm going by what I read but I thought the new map was to address high/low altitude problems with the original map.

[BRADEY]

Arizoni........the milder manners I spoke about are just my initial impressions. Of course when I take her out on a serious ride, I'll know more of her. So far she is behaving well. The stutter has gone out of system, this is because here in India the C5 comes with a open loop system, without the O2 sensor