Help - Engine Miss

[plrbear]

Hi all, I'm new to this whole street bike. I just picked up a 2006 FZ6 with 4,500 miles on the clock. Since I've had this It seems to have a miss thats most noticeable from idle to about 5000 RPMs above that it seems to have a vibration in the bars and seat also the throttle is really sensitive when your fist twisting it open. I have tried searching the forums and keep coming back empty so I decided to ask the experts (you guys:thumbup I've ran good fuel and seafoam though a couple tanks, replaced the plugs, sprayed ether around the intake/vacuum lines and had the throttle bodies synced twice still nothing. Any help you offer would be greatly appreciated.

 

[DDS]

checked spark plugs?

 

[Norbert]

could be normal.....

maybe post a video

 

[Kaisersoze]

Sounds like how my bike appears to normally operate. Has a slight miss when slowly revving but does NOT effect performance, and from what I gather most people (including myself) experience a decent amount of vibes. I scared me at first too because I thought something was terribly wrong but its just normal. If you arent having performance issues I would just try syncing the Throttle bodies (helped smooth idle out for me) and not waste too much summer weather with worrying. :BLAA:

good luck and congrats on bike!

 

[ebk02]

Okay - here goes. You replaced plugs and had carbs (injection?) synced. You need to get some tools, and take a ride. Get the bike to the point where it is missing the most and, hold it there for a bit. Now, pull clutch, chop throttle and hit kill switch all together. Get bike to side of road and pull plugs. If you have a lazy cylinder, that plug will look different than the other 3.
Also, check compression, and fuel delivery. This should point to which cylinder is causing the miss.

 

[Kaisersoze]

Okay - here goes. You replaced plugs and had carbs (injection?) synced. You need to get some tools, and take a ride. Get the bike to the point where it is missing the most and, hold it there for a bit. Now, pull clutch, chop throttle and hit kill switch all together. Get bike to side of road and pull plugs. If you have a lazy cylinder, that plug will look different than the other 3.
Also, check compression, and fuel delivery. This should point to which cylinder is causing the miss.

And wear gloves, because I couldnt imagine how hot its going to be if you been riding it and you stick your hand in there to get at plugs.

 

[plrbear]

Thanks for the input. i plan on grabbing some tools and gloves and going for a ride tomorrow.

 

[FinalImpact]

My used o8 doesn't sound like that at all. from 41xx miles to present (62xx); no miss, no hesitation, hardly any vibes to speak but maybe super high frequency/low movement aka hardly notice type vibes on the bar ends. The worst is maybe around 5400rpm.

IMO something is not well or at least as good as could be.

A squirt bottle full of water to the headers can help determine misfiring plugs. The longer it take to evaporate is the cooler or misfiring plugs. But it could but lean misfire too from inadequate fuel.

- run it in total darkness and look at the coils, caps, and wires for stray sparks. Mist the coils, caps, wires with water if day light is all you can do. IF the mist causes it to get worse you have an electrical issue.

Next I would be looking at the TPS. A bad spot could cause what you mention. Just an off idle hesitation.

 

[plrbear]

Thanks once again for all the input. I grabbed some tools and went for a ride. On separate occasions just as the miss would get really bad I'd kill the engine and coast to the side of road pull the plugs but each time there's no difference.

 

[DownrangeFuture]

If they're all a light grey and none of them are wet, it means it's probably fine. Every now and then a highly tuned engine will pop, stutter, etc. Usually that's caused by running just a tad lean. That's where the ECU will try to keep it. And it'll do it even more so when the engine is cold.

Ideally a cylinder will have just enough fuel to match the air flow and there is 100% burn in the cylinder. But that's really hard to measure as you'd have to measure intake volume for each cylinder and adjust it for the next burn cycle and that still won't get you 100% all the time. So it measures the amount of O2 in the exhaust and adjusts the fuel until there is only 1% or so. (because if you're rich then you've burnt all the air, but still have fuel and you can't measure that) That means a tiny bit of fuel gets into the exhaust and it can build up sometimes. That's what your catalitic converter is really trying to remove BTW.

My bike does it alot when it's cold, and not so much when it gets hot. The only real way to tell, is to buy the spark plugs with the glass window in them. Then you can see exactly what's going on. Adjust the fuel based on the color of the explosion. They're a pretty penny though. I'm considering buying some before too long so I can completely get rid of my popping.

 

[DownrangeFuture]

It stops over 5-6k because the ECU can't keep up with the changes, so it just free flows off whichever map it deems appropriate for the situation. Engines are the worst as far as emmisions at or near idle anyway.