Missing on right cylinder: I forgot most obvious cause (physics)!

[W800]

Hi Everyone,

I bought a new 2019 Kawasaki W800 Cafe recently.

Even before I did the 600 mile service, it was missing on the right cylinder when cold. Even when hot would sometimes "pop" on that side as well. Got more noticeable after I modded exhaust.

The rubber connectors between air box and TB, and TB and intake were super loose, but tightening them didn't fix problem.

I just lived with it, thinking I would eventually just take to dealer and let them figure it out. Then since I was already modding the bike, I thought it might sort itself out after I did some mods.

So, since I was planning this anyways, I installed piggyback ECU, bypassed air injection to exhaust ports, bypassed and capped O2 sensors, routed crankcase breather out of air box.

Also checked for any leaks in exhaust system and replaced both crush washers.

The only "yellow wire Morse code" error codes were the ones from when I ran bike before the O2 sensor bypass caps.

Problem did not go away. If anything, was getting worse.

So last night at around 11 P.M., I was sitting on my bed and realized what the problem (likely) was.

I went down to backyard and removed the gas tank. Pulled right plug wire.

Right spark plug was at least 3 turns loose!!!! I didn't really count, but I remember thinking that it must have been broken, or I didn't have the socket on properly or something. It just kept spinning and spinning. . .

Because it was a new bike, I didn't even think that a spark plug would be loose.

Still misses a tiny bit when cold, since I didn't want to pull the plug out in the dark (and when I was half-asleep). It's way down "into" the head, and I thought I might have some problems getting it threaded back in.

Will pull this weekend and clean both sets of threads, etc. . .

The reason why it missed only when cold was that aluminium expands more than steel under heat. See: https://www.engineeringtoolbox.com/thermal-expansion-metals-d_859.html

Once the bike warmed up, the aluminum head would "grow" enough to seal around the plug!

The reason there is still a very slight miss is likely that the threads of the plug are now very dirty, and hence it's still not getting a good electrical connection until the head heats up. If I still get slight miss after cleaning things up, then will attempt to diagnose secondary underlying problem (like a small intake leak somewhere).

Anyway, the lessons learned for me are:

1) Don't assume that the most obvious cause is not the cause.
2) If it's not air or fuel, by default it's spark.
3) Don't trust that threaded things stay tight.

 

[W800]

OK, it's still missing!

I posted earlier that I thought a badly seated plug was the cause of my 2019 Kawasaki W800 missing on the right cylinder when cold. The missing is not as bad now that I seated the plug and cleaned the threads.

But still missing (popping a little). Only when bike cold, and only on no load condition. Goes away after about 5 minutes. Also doesn't do in first few seconds.

Strange!!!

I have replaced the crush washers on the exhaust, and also checked for obvious intake leaks. I'm stumped!

I can't think of what would cause a 2 cylinder bike to miss only one side, but only when cold. Dirty injector? Valves set wrong at factory?

Cracked intake manifold?

Any guesses?

I'm going to let the dealer take a look at it, which is what I should have done from the start. Hoping they won't get mad at me for already modding the bike!!!!

 

[Hank Wong]

spark plug

Did you replace the plug? My guess is the spark plug still.

 

[W800]

Did you replace the plug? My guess is the spark plug still.

I think you are right. When I got home from work I regapped and reseated the plug. Gap was too small. Still misses a little but much improved.

The insulator was white, which I think is normal on a newer bike with low miles. The electrodes were darker than I would think they should be. I think maybe just bad plug from factory.

Will look up correct plugs and order a couple.

 

[motomania2007]

Have you checked for vacuum leaks?

 

[W800]

Have you checked for vacuum leaks?

I didn't see any obvious ones. I tightened where the TB goes into the manifold, and where the manifold connects to the head. Tonight (with engine idling) I sprayed some carb cleaner on the outside of the TB, thinking that maybe if there was a leak it would cause the engine to stumble a little. But it didn't cause a stumble. Possible that the intake manifold (which is plastic) may have a hairline crack, however. I was doing some research on this, and it looks like it was an issue with the older ones.

Hoping it's a just a crappy plug. I think the dealer will give me some grief, since I already rerouted the engine breather (out of the air box), made my own exhaust, added a piggyback ECU, and bypassed the exhaust air injection. It was doing the missing before all that, but they can say that I made it worse or something.

I was barely noticing it before the exhaust. But now that the bike is louder, it's noticeable. That being said, I will know tomorrow whether it's really improved when I do totally cold start. If there's any improvement, it's likely the plug.

As a side note, I don't have shop manual. So the first time I pulled the gas tank, it took an hour. Second time 10 minutes. Third and fourth times, 5 minutes, lol.

 

[motomania2007]

I didn't see any obvious ones. I tightened where the TB goes into the manifold, and where the manifold connects to the head. Tonight (with engine idling) I sprayed some carb cleaner on the outside of the TB, thinking that maybe if there was a leak it would cause the engine to stumble a little. But it didn't cause a stumble. Possible that the intake manifold (which is plastic) may have a hairline crack, however. I was doing some research on this, and it looks like it was an issue with the older ones.

Hoping it's a just a crappy plug. I think the dealer will give me some grief, since I already rerouted the engine breather (out of the air box), made my own exhaust, added a piggyback ECU, and bypassed the exhaust air injection. It was doing the missing before all that, but they can say that I made it worse or something.

I was barely noticing it before the exhaust. But now that the bike is louder, it's noticeable. That being said, I will know tomorrow whether it's really improved when I do totally cold start. If there's any improvement, it's likely the plug.

As a side note, I don't have shop manual. So the first time I pulled the gas tank, it took an hour. Second time 10 minutes. Third and fourth times, 5 minutes, lol.

The way you check for vacuum leaks and to start the bike and using WD40 or carb cleaner with a straw attached, then selectively squirt the WD40/carb cleaner around all vacuum ports and vacuum lines. A vacuum leak will result in the engine sucking in the WD40/carb cleaner through the leak and will cause the engine to stumble or accelerate.

 

[W800]

The way you check for vacuum leaks and to start the bike and using WD40 or carb cleaner with a straw attached, then selectively squirt the WD40/carb cleaner around all vacuum ports and vacuum lines. A vacuum leak will result in the engine sucking in the WD40/carb cleaner through the leak and will cause the engine to stumble or accelerate.

Ah. I didn't think to also do the lines. I did spray carb cleaner all around the throttle body, including where the vacuum lines go in - but I'll trace back some of those lines back out and spray their origins as well. My initial instinct was to use WD40, but I ended up using carb cleaner since it doesn't leave too much yuck after it evaporates.

I will check the lines again tomorrow, it's easy (since I don't have to pull tank).

Want to get shop manual. Pirated paper copies are $40 online, but I don't roll that way. I guess I will wait until Kawasaki gets them back in stock. I am thinking that more folks are working on bikes now, due to C19.

 

[CDONA]

Water in a spray bottle will do the same job without the fire hazard.
A vacuum leak will usually have a high idle, water will plug a little bit and pull the idle down. No muss, no fuss, no fire.

 

[dravnx]

No way is a dealer going to warranty any repair with all your mods.

 

[Eric B]

Did you check the 7th Fetzer valve?

 

[W800]

Water in a spray bottle will do the same job without the fire hazard.
A vacuum leak will usually have a high idle, water will plug a little bit and pull the idle down. No muss, no fuss, no fire.

Ah - good thinking! Will do it that way.

 

[W800]

No way is a dealer going to warranty any repair with all your mods.

Trueness. They called me this morning and were like "you can put the stock exhaust back on and we will check it."

I had to tell them that I cut the stock exhaust at the headpipes. I didn't mention the other mods.

The crazy thing is once I got the map down right, the bike runs really well (after it warms up). The miss is now super slight when cold.

Interestingly, when I owned a new Harley, I modded the heck out of that bike, and the dealer was always willing to look at it anyway (under warranty). I now think dealers use the federal smog regs as an excuse to not honor warranties.

 

[W800]

Did you check the 7th Fetzer valve?

Is that like the "TPS report?"

 

[W800]

Update. I went on the W800 FB group and chatted with some other W800 owners.

Someone told me that they had a similar issue. It was the fuel injector. Apparently (like mine) the bike had sat on dealer floor for a long time. Mine's a 2019, so at least 12 months, if not longer.

My plan is to contact Kawasaki USA via phone and see what they say. I did mod some stuff, but I didn't do anything that would make one side *only* miss. That sets aside the point that it was missing from delivery. What the mods DID do was make it much easier to notice the miss.

I also didn't touch injectors. They are $100 each. Not going to mess around with those!!!

Does anyone know the best phone number, other than 866-802-9381 for Kawasaki USA?

Does anyone with dealer connections know whether there is an ombudsman? I totally get the warranty issues. But a warranty is meaningless if I am held to blame for something I did not do.

 

[W800]

Update:

I wrote a detailed email last night to the dealer. I also "CC'ed" Roy Creed, who is the Vice President of Kawasaki USA, and a couple of other people there. The point of my email was that (1) problem has occurred from new, (2) "EPA" and "warranty" are two different things, (3) potentially violating EPA rules should not automatically invalidate this particular warranty as it's written, (4) even if the warranty is not applicable, general defective product laws and cases still apply, (5) if the dealer / Kawasaki USA do not wish to honor the factory warranty as a result of my mods, then the extended warranty I bought is also essentially worthless, (6) from a mechanical perspective, nothing I have done is actually capable of only affecting one cylinder.

Kudos to the dealership for getting back to me this morning. I am aware that they may be reading this thread. So I am just keeping it real. What's in the thread is what I told the dealer, and it's also what's in the email.

The nice thing about truth is that it's self-proving.

EDIT: TY to mods for merging the two threads I made on this issue.

Update. I went on the W800 FB group and chatted with some other W800 owners.

Someone told me that they had a similar issue. It was the fuel injector. Apparently (like mine) the bike had sat on dealer floor for a long time. Mine's a 2019, so at least 12 months, if not longer.

My plan is to contact Kawasaki USA via phone and see what they say. I did mod some stuff, but I didn't do anything that would make one side *only* miss. That sets aside the point that it was missing from delivery. What the mods DID do was make it much easier to notice the miss.

I also didn't touch injectors. They are $100 each. Not going to mess around with those!!!

Does anyone know the best phone number, other than 866-802-9381 for Kawasaki USA?

Does anyone with dealer connections know whether there is an ombudsman? I totally get the warranty issues. But a warranty is meaningless if I am held to blame for something I did not do.

 

[Tom G]

In order to prove your theory, can you swap the left with the right injector?

 

[Maddevill]

I own a Kawasaki. I generally like the company. But back in 1986 Kawasaki had thousands of bikes sold with really bad intake valves. The hard coating on the valve face was bad. My friends Ninja 1000 actually swallowed a valve. I contacted Kawasaki and, at first, they denied the problem existed. I explained I was a tech at a shop and I knew for a fact that what they saying wasn't true. They finally offered to supply parts. Refused labor

Mad

 

[W800]

In order to prove your theory, can you swap the left with the right injector?

Yes. Hoping dealer will try that so they don't blame me!

P.S. - The piggy back ECU I am using doesn't do different maps for each cylinder. What it does do is digital PWM (pulse width modulation), kind of like how a digital audio EQ would work.

It simply takes whatever signal is going to the injector and makes it last a portion of a millisecond longer or shorter. What this means is that you can also swap "sides" with the piggyback ECU.

 

[dravnx]

No, you swap injectors to find a bad injector. If you swap injectors and the problem stay with the cylinder, it's not the injector. If the problem moves with the injector, it's a bad injector. Electronically swapping injectors only proves the problem is upstream from the injector.