Bike crank but wouldn't start.

[Houtman_imp]

Sooner or later a batterie will die anyway , just buy a new one !

[zirconxi_imp]

While cranking, the neutral light went out. After few more tries the meter even reset after cranking. I tried jumping using battery from my ninja 650 battery. While cranking, neutral light still went out. Will try to get a new battery tomorrow and try again.

[Lord Popgun]

Well that pretty much verifies a bad battery. Just the very low cranking voltage does it for me. 8-9v is too low for the ECU to run on most vehicles.

[max]

Thanks Zirconxi, that confirms the suspicion i had about the neutral light, i found that it dims a bit when the bike cranks but now with your confirmation i think i can say that we can use that indication for a bad battery test; neutral light out = bad battery.

I'm with Popgun and the rest of the group to advice on a new battery.

In the meantime we found a new way to test a battery so thank you very much for that feedback, that was very useful and hopefully we can advice other members of it in the future.

And when you do install a new battery make sure the contact surfaces on the cables are very clean before connecting the new battery, with those 120 amp currents it is important to get all the available energy into the bike.

[zirconxi_imp]

Bad news, new battery crank like previously, but still no start, no spark, no fuel on crank, new battery voltage when key on, 12.7v, cranking will drop to 11v, then 10v, release crank n its go back to 12.6v. Neutral light no more dimmed on crank, new battery seems ok. .

[max]

unexpected indeed, well there is a check you can do on the crank shaft sensor.

No need to remove engine cover but locate the red connector with white and yellow wires under the right hand side cover near the air filter.
The white wire is connected to ground inside the ecu.
with the connector connected use a straightened paper clip to probe the yellow wire through the little rubber seal around the yellow wire, push it all the way in until contact is made and the meter indicates a value of ca.500 ohms.
With the engine and ignition off measure between the yellow wire and chassis ground, there should be close to 500 ohm resistance.
This is the "reluctor"coil, this coil times the spark and injectors, when the engine is running it produces 7 volts ac for the ecu.

So with engine cranking it should produce a little ac voltage like 1 volt or so i guess.

With the ignition switched on but engine off the yellow wire has 0,3 volts DC with respect to ground supplied from the ecu.

Check if the connections are in good shape and not corroded.

here is what the sensor looks like;


and;



And here is how it works;



I don't think that this part is broken but at this stage it needs to be eliminated as a possibility.
Hope that helps.

Just had an idea; are you sure you re-connected the ignition coil wires correctly when checking the valve clearance? they are a bit awkward to get to.

[zirconxi_imp]

Thanks Max for the instructions. Will test the shafts sensor. As for the ignition coil wires, i have run about 3000 km since i last did the VC. It did have this intermittent lost spark when hot after i did VC, but its rarely and intermittent, could it means i didn't put the coil cables correctly?

[zirconxi_imp]

Hi Max, i follow your instruction and it seems there is no ohm value between chassis and yellow cable. But there is some between white and chassis. Is there any way to tell if ecu or crank sensor is having problem? I plug in a copper cable all the way thru the rubber, tested it from the connector pin to make sure its shorted before plug it back. Tested with ignition off, yellow wire and chassis no ohm reading. Crank the bike and the white and yellow wire no voltage.

[max]

Ok, make one measurement;

1; unplug the connector and carefully measure the resistance between the white wire and the yellow wire of the connector that runs to the reluctor coil.

Backprobing ( with the paperclip ) can be difficult and takes a bit of practice to get the correct result so first test the ohm meter and see
with the two meter leads together if the reading is 0 ohms, then test the coil carefully.

If the coil is broken the reading will be much higher than 500 ohms, we want to make sure we get the right answer because it is important.

Sorry if i tell you what you already know but if we get this wrong it can be expensive,
i have looked online to find examples of defective coils but they are very reliable,
which is why we need to be 100% sure of the results.

[zirconxi_imp]

Hi Max, sorry but i am not well verse with electric and electronic. Thanks for being patient with me.
When i touch the 2 probing lead of the multimeter under ohm, there's some small value like 0.5 on the right of the meter, when its not touching it show as 1 at the far left corner.
When i poke the 2 probing pin into the socket of the sensor, it maintain as 1 on far left, as though theres no connection. I believe the circuit is open, but not sure if its supposed to be open or close when unplug from bike.