Twitching idle and stalling?

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chiech65

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Hi Guys,
I could use some advice. I have a 2006 with 90,000km.
I think I may need spark plug changed but want to see if there may be other issues.
Recently I noticed that at times took some extra tries to start my engine after filling up the tank. No issues when the engine is cold.
Today after a long ride, I noticed my idle was twitchy and not very stable. It smooths out when first riding, but as I ride more and come to a stop the idle becomes unstable. I have the idle set to about 1300 rpms.
The last sympton I noticed is that in when I am starting in first gear it seems extra jerky and the rpms dive a bit as if wanting to stall out. I actually had to ride the clutch more than I usually do to get the bike going.

Is checking my spark plugs the best bet? Anything else I should be checking while I am looking?
 
Spark plugs are a good place to start. You also might do the "paper towel" test where you check to make sure all cylinders are firing by checking the temps of your headers. Personally, I spray some water on them after the bike has warmed up a bit. The water sizzles as it boils off each pipe.

Something else to consider is the coils. I've had to replace them on my 2008, and it's something of a "known" problem with the Gen II's. My experience is that you can't reliably test the coils (with a volt-meter). Even worse, replacing the plugs masked the problem when I had it.

I'd be curious if anyone has developed a more reliable way to test the coils.
 
Once in a while I get that same hard start and erratic idle .ONLY ON HOT STARTS.

I suspect its a heat soaked sensor or the fuel getting too hot in the rail.

Once mine starts a few quick blips of the throttle seem to clear it up.


I've also noticed cycling the fuel pump twice ( turn the key on/off twice )
on hot starts helps the issue.

I assume its just pushing some hot, vaporized fuel around and letting her start/idle normal.

These Gen II FZ1's ( at least mine ) appear to get REAL hot under the tank.

This is a VERY common issue, I've seen it mentioned dozens of times.
Have not seen a " cure " yet.

Figure its just a quirk of the Gen II and not a big deal.

My best guess is its similar to vapor lock in a carburetor engine because cycling the fuel pump twice tends to fix or reduce my hot start issue.

I've considered adding some heat shield material under the tank to help insulate the fuel . I've seen self adhesive stuff available from " Jegs " or " Summit racing "

Mine takes 2-3 tries to start when this happens and then clears right up quickly if I blip the throttle or just start riding. So I just live with it .

Considering your mileage I'd also consider the airfilter, plugs and coils as others have already mentioned ! Coil issues are pretty common and often intermittent. Take look at your fuel line too, may be kinked. Search " fuel line mod "
 
Last edited:
terdog said:
What maintenance has been done? More info is needed. Cover the basics.
Click to expand...

I bought the bike about 7000Km ago and prior to that I do not have a maintenance record
The bike was given a maintenance check before I bought it. Since I have had the bike I changed the air filter and routine oil changes.

The bike did have a Ivan's FCE installed by the previous owner. Throttle response is great with minimum lag, so at least that is not a sympton.
 
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