(2006 FZ6) Misfiring/Running on Only 2 Cylinders

[Kid Amnesiac]

Been lurking this forum for a while (lots of invaluable information, have managed to do a lot of things on this bike thanks to this forum) so it is a bit unfortunate that my first post on here is in regards to what appears to be an electrical issue...

My 2006 FZ6 has been having a rough idle sometimes for the past month or so, my friends suggested I replace the battery as it is definitely a bit old. I went and put in a lithium battery where you have the fill the empty space in the battery tray with foam (battery is much smaller than the AGM that was in there), not sure if that would cause any problems but either way I started it last night after the swap, idled fine. Went to ride this afternoon and it idled lower but I didn’t think too much of it until I got going and it occurred to me that it sounded like a parallel twin instead of an i4 and it was very, very stutter-y/boggy, in other words it would appear I was only running on 2 cylinders. After riding it for a bit the issue seemed to subside or at least improve to the point where it felt "okay", however after letting it sit for a while it again appeared to be running on only 2 cylinders. All this to say either the battery I installed messed something up and is the cause (which i feel is unlikely), my spark plugs are acting up (which I have not changed as I was told by the previous owner were swapped for NGK iridiums so I believed I should be fine for a while), or one of my two ignition coils is shot.

Any other perspectives on what might be the problem would be appreciated.

 

[grahammarsden]

First thing: Run the bike for a bit to warm it up, then wet your fingers and tap each of the downpipes and see if any of them feel cooler than the others.

Note that cylinders 1 and 4 run off one HT lead, 2 and 3 run off the other, so if one of these pairs are cold, that suggests the cause (although that should flag up an error code on the instrument cluster).

If this does happen, swap over the plug caps between the pairs and see if the cooler pipes change places.

Another issue could be a faulty injector, if that's the case, swapping the plug leads over won't change it.

 

[Motogiro]

First thing: Run the bike for a bit to warm it up, then wet your fingers and tap each of the downpipes and see if any of them feel cooler than the others.

Note that cylinders 1 and 4 run off one HT lead, 2 and 3 run off the other, so if one of these pairs are cold, that suggests the cause (although that should flag up an error code on the instrument cluster).

If this does happen, swap over the plug caps between the pairs and see if the cooler pipes change places.

Another issue could be a faulty injector, if that's the case, swapping the plug leads over won't change it.

On swapping plug wires you would also need to swap primary feeds on the coils.
Is there an error code?
There may be a possibility a primary wire on the offending coils has come loose.

 

[Gary in NJ]

Don’t touch the head pipes with your fingers…even wet. It’s painful. Use an IR thermometer.

Just under the battery box are the ignition coils. My guess is when you installed the battery (maybe trying to squeeze it between the foam blocks) you dislodged a +12VDC or trigger wire to a coil. Recheck your work.

 

[grahammarsden]

Don’t touch the head pipes with your fingers…even wet. It’s painful. Use an IR thermometer.

Mythbusters: Dipping your hand into molten lead

Just saying

 

[Motogiro]

Mythbusters: Dipping your hand into molten lead

Just saying

LOL! I'm still not pissing on a spark plug to see if there's spark...

If there is no error code there may be a problem on the high tension side which is causing the miss. Is there an error code?

 

[TownsendsFJR1300]

Squirting water (a small amount) on the header (near the head) will quickly sizzle off of that cylinder is working fully.
.

.
Use any squirt bottle with water

 

[Motogiro]

Wait......hear that? ....... Anyone hearing crickets?

 

[Gary in NJ]

He is reading…just not responding.

 

[TownsendsFJR1300]

Maybe looking for water?

Maybe looking for crickets?


.

 

[Kid Amnesiac]

Hey folks, thank you for the replies. Looks like I’ve got some things to check when I get the opportunity. There’s been quite a bit of rain and some windstorms in the PNW and seeing as I keep the bike covered outside I haven’t been able to inspect anything for now.

Weather should clear up on Thursday and I’ve got new plugs coming in so that’ll be a good time to check for all these things. Will hopefully update with any new findings then.

 

[Kid Amnesiac]

So I wasn’t able to swap my plugs today but I put the old battery back in to see if that would make a difference (it did not, but I figured it was worth a try to see if that might’ve affected something).

I then went into diag mode to see if there were any clues there and got codes 12, 30, and 46, 46 being the most likely culprit here seeing as that implies there is/was an issue with the charging system. Cleared the codes and after letting it idle for a bit and checking again there weren’t any codes so unless I forgot something the bike doesn’t think there’s an issue…

I’ll test for other things when I have a chance but it looks like the weather is going to be rain, rain, and more rain for at least a week straight so it might be a while until I have an opportunity to dig deeper.

On the bright side this started happening during the off season so at least I’m not missing out on good riding conditions…

 

[Kid Amnesiac]

Update:
Finally managed to have a day off work where it wasn't raining so I limped the bike to a friend's.

While we had the battery box and coils removed to swap the plugs we checked the resistances on the coils and all seemed to be within spec and close to each other which indicated the coils weren't the issue, the plugs seemed okay save for cylinder #3's plug which was wet, indicating that was likely our problem cylinder (it also means I was technically running on 3 cylinders instead of 4 so instead of having an FZ3 I had an FZ450 )

Sure enough we tested the plug caps for continuity and #3's cap was very inconsistent, we trimmed the lead for it a little bit and screwed the cap tight and sure enough all seemed well. Put everything back together and started the bike up and it idled even smoother than when I first got the bike so evidently this had been a problem for some time and had just progressively gotten worse. Rode it home and it ran like clockwork and has continued to do so.

Problem solved! Of all the things it could've been I'm surprised (and glad) that it ended up being a very simple fix and I have known good plugs in the bike now so that's a bonus. Onwards and upwards from here, glad to have my Fazer up and running again.

 

[trepetti]

Update:
Finally managed to have a day off work where it wasn't raining so I limped the bike to a friend's.

While we had the battery box and coils removed to swap the plugs we checked the resistances on the coils and all seemed to be within spec and close to each other which indicated the coils weren't the issue, the plugs seemed okay save for cylinder #3's plug which was wet, indicating that was likely our problem cylinder (it also means I was technically running on 3 cylinders instead of 4 so instead of having an FZ3 I had an FZ450 )

Sure enough we tested the plug caps for continuity and #3's cap was very inconsistent, we trimmed the lead for it a little bit and screwed the cap tight and sure enough all seemed well. Put everything back together and started the bike up and it idled even smoother than when I first got the bike so evidently this had been a problem for some time and had just progressively gotten worse. Rode it home and it ran like clockwork and has continued to do so.

Problem solved! Of all the things it could've been I'm surprised (and glad) that it ended up being a very simple fix and I have known good plugs in the bike now so that's a bonus. Onwards and upwards from here, glad to have my Fazer up and running again.

Excellent. The FZ6 has a few weak points that always seem to crop up. The spark plug boots are definitely one of them. One of our form members, FinalImpact, did an extensive study here. https://www.600riders.com/threads/v...-vibrations-spark-plug-caps.48874/post-654362.

The other thing to watch for going forward is the kill switch, which has a habit of intermittently cutting in and our at high revs (when there is lots of vibrations) making resulting in a loss of power. It doesn't mean yours will encounter this issue, but it's always good to know what others have experienced so we don't need to reinvent the wheel. That is the whole point of this forum.

Stick around. The folks here will help you get many enjoyable years out of this great bike.