Motorbike Doesn't start, you can hear it like is fine but it seems that don't get spark

[javito]

Hi All,

I'm new in this forum however I've been riding for a few years already. I have a Yamaha FZ6N 2006.
I just came back from my work (30 minutes ride) a few days ago and the day after it didn't start.
You can hear the start common noise (something like yan yan yan yan I guess) and you can even see the revolutions going up, but nothing.

- It's not the kill switch
- I tried it in neutral and in first gear too (just in case it was the step switch)
It's not battery because:
- the battery is new (2 months)
- the day before I was riding it and not a problem
- I tried to push it to start it up (I went through a downhill that It should start it if it was a battery issue)

My theory is that it's an electric issue because I can smell the fuel if I use the throttle.
I didn't check the spark plugs if there is any spark when I press the start button
I checked the fuses and they are ok (the fuses that are at rear on the right hand side).

I was checking the Workshop manual and the troubleshooting says to check a few things and the next step would be the ignition coil.
I just opened the tank and I can see the ignition coils there, however I noticed there are 2 ignition coil (1 per 2 spark plugs) so my question is:
is it possible to be the ignition coil? if so, both of them should be broken because if at least one of them is working it should at least try to start, badly but at least try.

I'm not a mechanic I just have some working knowledge about engines and electric systems, and I just wanted to see if it might be something I might be able to fix.

Any recommendation or comment will be more than welcome.
Thanks everyone
Javier

 

[ChevyFazer]

Welcome to the forum!

As for your problem, I wouldn't right off the battery just yet. If you haven't actually tested the voltage then you don't know for sure weather it's good or not. I'd say it's a VERY LONG SHOT that the coils have gone bad, and if you are smelling fuel then you have probably flooded it.

 

[iSteve]

Before you go any further check for spark.

 

[Motogiro]

As mentioned. the battery could be bad even if 2 months old. The battery must have it's charge maintained and can fail at anytime for many reasons. Check the battery voltage with everything off and then on and then while cranking. It should be 12 volts and above regardless of cranking or not. If you are getting fuel in (you can smell it.) then it sounds like there is no spark. Is that what the yah yah yah yah sound is? So I'm guessing the starter is cranking the motor over correct? Or is the fuel smell only from bump starting? If it were the kill switch the starter will not crank. The kill switch does feed the coils primary winding directly with voltage and the ECU circuits operate the ground side of the primary windings for firing.

My starter sounds like this ; shcur gur gur gur gur gur gur gur

 

[FinalImpact]

In short we need more info -

Lets say the bike is ridden daily and you didn't fill with fuel recently and it wasn't sitting out in the rain with the fuel cap open. Its been running reliably for 10,000km. . . but why did you replace the battery 2 months ago?

1) So we assume it has petrol which is clean, burns, and IT was running on it = Not a fuel quality issue. But honestly this means nothing as your last fill up could have load of water in it.
2) You hear the fuel pump activate when the key is switched on.
3) It sounds to crank over at normal speed as it had for the last 10,000km (it reliably go yan yan yan yan and/OR shcur gur gur gur gur gur gur gur!).
4) As Chev stated, not likely the coils both crap at once.
5) No error codes displayed
6) Crank + Spark + Fuel + Air = runs. . . So which is missing?

how was it running the last few times out? ANYTHING out of the norm? Rough idle, missing , shaking, hesitation?

I'd pull the plugs and look at them. Connect them to the caps and crank it over. All 4 should have a nice purple white spark across the gap. Orange red is no good.

Get a DMM/volt meter and get a battery reading as suggested.

Report back what you know!