Sputtering only at full temp

[moto_jojo]

Looking for a bit of help here. I ride my 2006 FZ6 as my daily commuter. Over the past couple of months it has developed a shutter/sputter/miss at low RPM (1000-2300), but only when the engine is up to normal temp. Most of the time I only notice it near the end of my 15 minute commute, but it gets worse the longer I ride. It starts fine every time, idles great cold, and runs like a champ otherwise. Only when idling or trying to take off once the engine is warm does the issue present itself. It doesn't ever die, but it tries.

Given that the bike starts fine every time, I think I can rule out a battery issue. But I am really not sure what would affect the engine so much hot, but not when cold.

All advice is greatly appreciated!!

 

[Motogiro]

:welcome: to our great forum!
It almost sounds like a fuel supply issue. Check that your fuel and vent line are not hindered or kinked. Maybe some fuel injector cleaner like SeaFoam added to fuel.
The kill switch is known to give intermittent performance that can be affected my vibration of the bike.

 

[moto_jojo]

Motogiro,

Thanks for the tip. I have been working on the bike all day today. I checked that the lines were not kinked or damaged. It has had Seaform twice already since the issue began. How ever I did note a new finding. I have an custom LED kit that I had for a while, don't really use it though. Most of the negative side connections and wiring toward the front half of the bike were corroded and were basically dust in the plastic. I thought maybe this was causing a small short at times and causing the pump or plugs to lose power.

Today, I ripped out all the bad wire and replaced nearly all the connections. Tested every along the way. Sealed everything better too. I'll be riding my normal commute tomorrow so I should have an update if this fixed anything or not.

 

[TownsendsFJR1300]

When's the last time the spark plugs were changed?

And what's your Idle RPM set at?

 

[moto_jojo]

Well, still present after the wiring for the LED's was replaced.

Townsend, the plugs were replaced about 2 years ago. However this reminded me of something. I did the plug replacement myself then, but about a week later, the issues I have bow, I had after installing new plugs. Took it to the dealer whom charged me $200 to tell me the boot was loose an #1 plug.

Now when this first started a couple months ago, I checked this first. However, it still might be plug or coil related. I'll try to look at the plugs this week and replace those along with the coils if possible this week and will keep you all posted.

Thanks for all the advice so far!! I do have a video of the bad idle and I'll try to post that later today.

 

[moto_jojo]

I also found this thread below where you two were helping another rider with similar issues. Noting the above mentioned spark plug issues, I really thing it might be plug or coil related. I will check more and let you know.

https://www.600riders.com/forum/fz6-electrical/45502-possible-bad-coil-pack-10.html

 

[TownsendsFJR1300]

Please try installing the factory, NEW, OEM, 2 prong plugs.

If you damaged the tip of the iridium's, that would mess them up...

Also, when re-installing the caps over the plugs, put some dielectric grease on the rubber where it meets the valve cover and the rubber(right there) as well.
The caps tend to harden with the many heat cycles/age and make it difficult to SNAP ON THE PLUG.

If you don't HEAR / FEEL the cap snap onto the plug, it's NOT ON... The grease won't hurt anything and make the install WAY EASIER...

If you have access to a lazer temp gun, point it at the top of the header when the engine is acting up. You may see a lower temp on one header if you have a coil /cylinder not firing. Also, inspecting the plugs may show one with a much different color than the others...


* Not on an FZ, but a customers Yamaha golf cart that wouldn't run (gas, 4 stroke). Had spark at the wire end, tried grounding the plug on the block-spark would come and go. Closer inspection showed the electrode loose (broke) in the center of the ceramic... New plug, cranked right up...

 

[moto_jojo]

So some possible progress!! I took the plugs out and examined each of them. They all looked fine. No fouling, damage or carbon. Had to ride it in the morning so put everything back together and so far it the issues has not come back.

Judging by where the boot was on #1 I believe the boot might not have been 100% down, but more like 95%. Got a much better seal on it down and it has not sputtered since. I'll be riding over the next couple days and will report back. Thank you you two for your help. Hopefully that fixed it.