Cylinder Not Firing?

[AlisAquilae]

Hello,

I just trailered my FZ6 1100 miles to the site of my new job. On the first ride after taking it off the trailer, I noticed that the exhaust note was significantly different than usual, the bike had trouble accelerating and power felt low. I rode around for about half an hour, then parked the motorcycle. Before the bike cooled I was able to spray a bit of water (don't have an IR thermometer) on each of the headers and noticed that the 2nd cylinder header was not hot at all. My idle RPM is around 900 - no engine codes.

Any ideas on how to diagnose this issue/what to check first? Plugs?


Thanks!

 

[FinalImpact]

Correct ^^ !! I would start with the wires, caps, plugs. Even today spark plugs do fail so I would simply replace them while you are there. Do not exceed the gap specified for the FZ6 engine by Yamaha no matter what new plugs you buy.

If going OEM route I would opt for CR9E (no K) and run the single strap ground electrode or spend more and get a precious metal plug of some kind.

How many miles on the bike and have the valves ever been checked?

 

[AlisAquilae]

Thanks for the reply! 8500 miles, valves have never been checked. To clarify, you are suggesting as a first step that I check the plugs/wires and go ahead an replace all plugs while I have them apart?

I included the anecdote about trailering because I was wondering if the vibrations/jolts from the trailer could have knocked something loose. Is this a possibility?

 

[The_Paragon]

If going OEM route I would opt for CR9E (no K) and run the single strap ground electrode

Why the CR9E but not the CR9EK? My better half has an FZ6R, which calls for the single strap CR9E, where as the Fz6's call for the double strap CR9EK. I always wondered why Yamaha made that change. or what the difference is.

Also the 03-05 R6 calls for a CR10EK, but its pretty much the same engine as our fz6..

 

[FinalImpact]

Why the CR9E but not the CR9EK? My better half has an FZ6R, which calls for the single strap CR9E, where as the Fz6's call for the double strap CR9EK. I always wondered why Yamaha made that change. or what the difference is.

Also the 03-05 R6 calls for a CR10EK, but its pretty much the same engine as our fz6..

Short answer is less to go wrong!
Mainly for the rate of decay from the center electrode. The K or double strap plugs show significant gap increase towards end of the plugs life cycle while the single strap just gets rounded but generally still maintains the same gap distance, while the K's increase the gap which can induce other issues.
Also, being a waste spark system these plugs are subject to increased wear from firing double the rate of the 4 cycle engine power stroke. It's why many replace them Iridium or other precious metal plugs. Notice those do not come as double ground strap.

 

[TownsendsFJR1300]

Just trailering the bike shouldn't be an issue.

Was the bike / trailer parked somewhere it could have been screwed with (during the road trip)??? I would be looking real hard at anything easily accessible while the bike was on the trailer...

Pull the spark plugs, and please post a pic of #2 plug. It should be tan but is likely black/fouled at this point...

If you started and turned off the engine while still in the cold mode, its possible(not likely) you did foul the plug.

If you have a spare plug, plug it into the #2 spark plug cap, ground it and crank over looking for spark. . Please post whether you have spark or not.

If your bike is stock, IMO, just put in original temp Iridiums. Yamaha put that temp in for a reason. They don't cost much more at all and you won't have to change them again. Check the gap, and no their NOT pre gapped for the FZ but are usually pretty close. NGK Spark Plugs USA

BTW, you can replace the plugs from the right side of the bike, leaving the radiator in. It is tight, you will have scruffed knuckle,s but its do-able. Some dilectric grease on the cap will make re-installation MUCH easier.

If you have some air, blow it in the spark plug hole before you pull the plug. You don't want to drop any crap into the combustion chamber..

 

[AlisAquilae]

1. Trailer is enclosed and locked so I don't think it could have been tampered with.

2. It will be a week or two before i have the opportunity to pull the plugs due to traveling. I will try to post results when I do.

Are these the iridium plugs you are suggesting?: NGK Spark Plugs USA
Iridium
CR9EIX
Stock Number 3521

3. Is there a write-up or a video somewhere that outlines the spark plug replacement process?

4. In the meantime, will it be damaging to the engine to ride as is?


Thank you.

 

[TownsendsFJR1300]

Tks for the update.

I can't open that link, (goes elsewhere), whatever NGK calls for but that's probably correct.

Re replacement, its in the shop manual but you can do some short cuts. Loosen but don't drain the radiator, it'll give you a little more room. Use the stock cheap Yamaha spark plug socket. You CAN sneak an inch lb torque wrench in there when re-assembling. There's numerous threads here about checking the spark plug caps as well.

Will it hurt anything riding it now? probably not BUT I wouldn't. You may cause more damage if there's something serious to it..

Also, if you want to check to see if #2 IS GETTING FUEL, pull the air cleaner, and start the engine. Squirt just a little bit of fuel down #2 throttle body and see if it fires/hits. That would point to a fuel issue (perhaps a clogged injector, or? )


PM sent

 

[iSteve]

Don't ride if you think you dropped a cylinder. Just take 15 minutes pull the suspected bad plug and see what it looks like. Check if it sparks.

 

[AlisAquilae]

Will do. I just read this write-up (How to: Replace your sparkplugs in 20 minutes - Sportbikes.net) on how to remove the plugs and the process is much shorter than I had anticipated. I'll look at the plugs tomorrow and report back with some pictures.

Thanks for the replies.

 

[TownsendsFJR1300]

Did you get my PM???

 

[AlisAquilae]

I pulled the plugs earlier today and found the following:

#2 plug in #2 boot gives no spark
#2 plug in #4 boot gives no spark
#4 plug in #4 boot gives spark
#4 plug in #2 boot gives spark
#2 plug and #4 plug look the same

I've drawn the conclusion that the only component broken is #2 plug. #2 boot seems to work fine with the functional #4 plug. I'll be buying new plugs today but the Autozone down the road has only the CR9E regular plug.


Images of the #2 plug

http://i.imgur.com/xIzB2Rf.jpg
http://i.imgur.com/jNQZLmC.jpg

 

[TownsendsFJR1300]

Agreed. You can adjust the plug gap with a round tipped feeler gauge. I'd put them on the tighter side as the gap opens with wear and tear.

The center electrode in the second pic looks worn, you can see right at the tip, its THINNER. I suspect the gap was too much for the spark.

Please post back.


BTW, wasn't too bad to get to was it?

 

[AlisAquilae]

Gotcha: set closer to 0.024" per the manual's range of 0.024"-0.028".

Wasn't too bad at all - luckily I happened to have a 14mm combo wrench on hand that I bought separately to change the front driveshaft u-joint in my truck. My socket and wrench sets are shipped to my new job site and I do not have access to them for another week or two - hence why I thought I wouldn't be able to do it immediately.

Will post back on results when I get the new plugs in.

 

[TownsendsFJR1300]

Perfect!

Make sure you hear the caps SNAP onto the plugs.

The dilectric grease would help with that as the caps tend to stick on the valve cover...

 

[FinalImpact]

Likely too late now, but if you should find some vibrations that rock you to the core (think chassis harmonics) through the seat and bars, some of the wire to cap connection has been known to fail. Simple test is to hold the wire and gently rotate the cap clockwise. It should snup up tight and NOT continue turning. If the spin, unscrew them and cut off a 1/4" of the wire. Thread it back together.

Did you go with the CR9E plug? It works fine!

 

[AlisAquilae]

Replaced all four plugs with CR9Es and everything works great! I had about two gallons left in the tank and added two ounces of seafoam to it as an added measure. The combination of these two fixes has really cleared up any issues that my FZ6 was having - cylinder misfiring, sluggish acceleration, low idle rpm and erratic rpm jumps while running.

Thanks for all the advice!