FE390 Eats Spark Plugs Like Potato Chips

Ok, this is a long story, but I think you will find it interesting.

As some of you may have read on the “Vapor Lock” post, I dealt with a bad fuel pump for a while. Ultimately, my dealer sent me the pump from his demo bike and that fixed my problem. When he sent me the fuel pump, I had him send me a new spark plug too. With the new pump, I got to ride my bike without incident for three whole rides and a total of 6.8 hours! I was happy!

Then, I loaded up to ride again, and it wouldn’t run. It ran perfectly fine for those 6.8 hours, but now it wouldn’t idle. It would fire but then die. WTF!? I tested the fuel pressure and TPS; both were fine. After two weeks of checking everything, I checked the almost-new spark plug. Although it looked fine, I replace it and the problem went away! The idea that a new $20 plug would only last 6.8 hours was surprising, but I figured I just got a bad one.

So with my new plug I set out again. This time, I get 7.2 miles into my ride and my front tire kicks up a rock. I hear a bang and then a grinding sound. I hit the kill button and inspect the bike. Nothing. My buddies ride up and help me inspect. We find nothing. I hit the starter, it fires, but makes a horrible grinding noise. I shut it off and discover the rock went through the clutch cover, my clutch basket is hitting the caved-in section of the cover, and I'm leaking oil badly. I get towed back to the trailer.

I replace the clutch cover, install a genuine Husaberg aluminum skid plate and head back out the following weekend. I have a great day! My mojo is working, the bike is working, the weather is great. Every once in a while the bike coughs, but it doesn’t stall. A couple of times it doesn’t fire right up, but it always does after a second or so. I figure I just have old gas (which I do) which isn’t formulated for the colder temperatures. I complete my ride incident free and I’m smiling! I love this bike!

I get home, wash the bike, start it up, and put it away. A couple of hours later I start it up again to oil the chain and it coughs and dies. It won’t restart! Do I laugh or cry? I fully charge the battery and it still won’t start! I check for spark with my old plug and I have good spark. I pull the plug and it’s wet with gas. WTF!!!?? Could it be the new spark plug with only 2.7 hours on it? I check it. No spark! I see an arc go from the cap to the insulator. Sure enough, the insulator has an obvious crack in it! I put the original spark plug in and it fires right up and runs like a champion.

Am I cursed? Does the Husaberg god hate me? How can I go through $20 spark plugs so quickly? I’m careful when I install them. I don’t over tighten them and I don't drop them. Am I the only one who has this problem? For my 52nd birthday last week I wished for three consecutive uneventful rides. I only got one.

Wow! I felt your pain with the fuel pump but lucky for me I haven't had the spark plug issue. Good luck.

Maybe a rock hit the spark plug too?

if your bike misses a beat every now and again as if someone had tapped a morse code button but the bike carries on as normal I'd say that you are so rich that the plug is on the edge of failing. i bet your MPG is on the floor right?

try and get a plug that is one grade lower as an experiment. an 8 instead of a 9 for instance.

regards

Taffy

Taffy said:

if your bike misses a beat every now and again as if someone had tapped a morse code button but the bike carries on as normal I'd say that you are so rich that the plug is on the edge of failing. i bet your MPG is on the floor right?

try and get a plug that is one grade lower as an experiment. an 8 instead of a 9 for instance.

regards

Taffy

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Thanks for the idea. My gas consumption is fine. Also, my plug has the just-right brown color. It's not black at all, so I really don't think it's rich. The crack couldn't have been caused by incorrect mixture. I'm going to buy a Motion Pro plug wrench, two new plugs, and insert a new one after I meditate! (I'm never going to ride without a spare plug in my tool kit.)

check plug cap as they can develop a fault, also check earth connectors on frame at ht coil.

midwest said:

check plug cap as they can develop a fault, also check earth connectors on frame at ht coil.

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Thanks midwest. What should I look for on the plug cap? I looked at it and even scratched my butt while doing so but I didn't see anything. I'll check the ground. Could a loose ground cause plugs to fail early? I'd imagine a loose ground would cause the whole electrical system to "flicker" or die.

We had (1) 2010 FE390 come in our shop with the same issue. The top porcelin part of the plug had a crack in it. We found no reason for it to have failed. The plug cap looked perfect. It was not the original plug in the bike. The customer had changed it once so we chaulked it up to him causing the crack when he installed it. Could they be getting slammed around during the shipping process somewhere along they way causeing them to become weak? I am open to any thoughts on this....................

Sounds like an issue during fitment. What sort of plug socket are you using . Take care in making sure you don't put axial load on the plug during installation.. Especially if replacing the plug fixes the problem and you find cracks in the porcelain.

Here's a photo of the crack. I find it hard to believe that I did this when I installed the plug. I've installed many plugs over the years and have never had a problem.

It wouldn't be a case of a bad batch of plugs would it? I seem to remember there was a mention of bad plugs by a couple of other folk a few months ago. They replaced there old plugs with new only to have them break down after a short periode of time. Bikes ran fine when old plugs reinstalled.
Are all the plugs broken in the same place?
Do those having plug trouble support the top of the plug spanner whilst turning to prevent excess axial loading?
Just a thort.

The plug in your picture looks exactly like the plug we took out of the bike that came in our shop with the issue. My vote is that it was a bad batch of plugs.

Yeah, that's my vote too. I've rebuit car engines and transmission, built a "wing" of my house, and built most of the furniture in my house. I'm pretty good with my hands and I think installing a spark plug is within my limits.

Although, being cursed seems plausible too.

I looked at the other plug (replacement number 2) with a magnifying glass. I can't find anything wrong with it. However, when I reinstall the original plug with 30 hours on it, the bike starts instantly, idles with gusto, and just runs stronger. With plug number 2, it doesn't do any of that. NGK has been making plugs forever so it's strange that all of a sudden they make bad ones??

I've also had the same issue with my 450, always carry a plug with me now just in case, I use an ordinary plug not those ultra expensive iridium plugs, i certainly can't tell any difference between the two except for the extra cash in my wallet.

I'm always very careful when installing the plug not to side load it when doing it up, never had the problem again so far.

do this issue happen once the bike heats up??? I have a brand new 2010 390 that once hot, 10-15 minutes into the ride starts coughing and stalling, let it cool off and it's fine?? was thinking fuel filter problem but after reading this I'm going to check my plug tonight...

does anyone know of a good replacement plug number instead of the oem $20 plug??

I had to have a new plug cap after 25 hours, They checked it while doing the tappets and found there was not enough resistance in it.
I did not know there where 2 types of plug caps. resisted and non resisted, Not sure if this will help you out any

what where your symptoms with the bad plug cap?

Nothing that i noticed, Maybe he caught it just as it went wrong.
If the plug cap plays up would it make the bike eat plugs ?.

My brother was having a similar issue of not keeping the bike idling after it got wet from knee high water crossing. The bike refused to idle until it dried off (about 5 minutes.) He went home and using a spray bottle with water sprayed the spark plug wire, he could see a spark jump from the wire to the radiator. Faulty wire.

My friends bike died in the trail would start up but stall out. After changing fuel pump ,fuel filter , driving all over to get the injector cleaned and the filter on that replaced, (yes it has a filter on it ). Its then put back together starts and runs but it would occasionally miss during idle and if the throttle was cracked it would stumble or stall while idling and after a run down the block and heated up it would just stall out. Swapped plugs from my bike and it runs perfect. The plug does not completely fail but makes the bike run terrible like its starving for fuel. Check the small things first !!!