Totally rusted coil/spark plug

[Moho Miner]

Hi guys,

I know I don't post here often, but with this little doozie of a problem I thought I would.

On Friday after work started up the bike, ran fine although a little irratic for about 15 seconds and then dropped to one cylinder - I knew that one of the plugs/coils had probably failed. Rode very noisily/slowly home. After getting down to the coils/plugs, the first cylinder coil/plugs 1 & 2 were okay (that was the cylinder that got me home!) but the second cylinder was bad, got out coil/plug 4 but it was rusted - plug below is from plug 4. Coil/Plug 3 is done, i've never seen a coil so rusted in - basically in my efforts to get that bad boy out of there its totally snapped off, you can see that below.

I'm really in an iffy spot now, there are literally only two options left. My first option and plan is to take the cylinder head off the engine and therefore expose more of the knackered coil to get it out, will have to be a little careful with this one as there is a potential for me to get lots of rust shit down in the engine. The second is to somehow drill parts of the coil out - but with limited access that could be tricky/risky.

Anyway, that was my weekend - I'm sort of confident that the head off tactic will work but I might be eating my words soon.........

Keelan

 

[Dogdaze]

The rusting coil stick is not a new issue, many UK riders have had this issue, as well as those that live in damp/ humid areas of the world. If left in too long between services they will corrode and f**k up your day/week. There are various threads on this topic. Even recently as two weeks ago, also some have found really inexpensive replacement coils, as Yamaha main dealers like to charge @£70each

 

[SilverBullet]

Is the material of the coil robust enough to hold a couple very small screws? Then you could grab both screw heads at same time and twist and pull to remove? Worth a shot at least. Use a little penetrating oil around the circumference of the coil also to make it easier.

_

 

[2daMax]

Silver's idea spark off this idea.

1. Drill like a 6mm through the coil, maybe up to 4cm in. Hopefully with this action, the coil and plug would have loosen up.
2. If still stuck, use a M6 bolt, laced it with Silver Epoxy and stick into drilled hole leaving a good length of it for gripping. Let cure as directed. Then with all your might, pull that bolt and hopefully it comes off.
3. If the bolt comes off and the coil is still stuck, use a larger drill like a 10mm and drill it till u hit the plug. The stuck areas would be the plug's terminal nut, I assume, and once u drill this part, it should be free to come off. Hopefully the Hex nut on the plug is still good to be removed.

 

[Moho Miner]

Thanks guys, thats not a bad idea actually. Problem is always the access but I might give this a go. I was thinking if I butcher it enough it would fall to pieces and come out eventually??

Let me give it a go and report back.

K

 

[RCinNC]

As long at the spark plug's still in place and acting as a stopper in the cylinder head, why not just fill the spark plug well with a solvent like PB Blaster and let it sit for a day? After that, pump the solvent out of the well with something like a Mity Vac (or even a siphon, if you're brave), grab what's left of the coil stick with some pliers, and ease it out? A day's worth of soaking in a good penetrating solvent should break that rusted connection between the coil and the plug, and since the coil's trashed, you don't have to be concerned that the exposure to the solvent would do any harm to the coil.

 

[Kevhunts]

Once you get that broken coil stalk out of there, if you find the spark plug hex to be corroded and rounded off, Sealey sells a brand of sockets called "Lock-on" that is touted to remove such items from tight recessed spaces such as the spark plug well. Good Luck!

https://www.youtube.com/watch?v=zTTlQJX9Rug

 

[stutrump]

I've had exactly the same. Took the head off.
Once you've sorted it please remove the metal sleeves that wrap around the coils. That really helps prevent it happening again

 

[stutrump]

PS..I've done 60,000 miles+ on mine without those metal sleeves and no probs

 

[Don in Lodi]

I think if you can get the valve cover off you will expose a good half to 3/4 of an inch of the offending coil stem. Might give you enough material to twist and pull on.

 

[stutrump]

Moho Miner..just for future reference if you ever need a hand Im often staying in Cheltenham (probably not far from you) but Im crazy busy with work at the moment sorry. Maybe keep trying to get it out first but dont worry about taking the head off if you have too..it worked ok for me

 

[Moho Miner]

Thanks so much for the replies and support, I've spend a good few hours today trying to sort this, unfortunately I think it's game over for my part and it's going to have to go the dealer. The coil sort of disintegrated into pieces the first inch, I think that taking the head off will not revealed anything more now....

I think it's got to the state that the dealer may have to drop the engine from the bike now. I could do it myself but I just don't have time what with work. Pretty disappointed as I know it's going to cost a chunk. The coil is in such a melded state with the block that after getting a self tapping bolt drilled into it, the hammer I was using the wrench it out actually bent. It's really bad.

I'm with you on removing the metal sleeve, what they were thinking with this design I just don't know.

 

[stutrump]

Yes, the metal sleeve is stupid and in 60,000 miles without them I can say its uneccesary too. Sorry to hear that your out of options or to be more precise..out of time. Hope it's all sorted soon

 

[SilverBullet]

Curious about this rusting of the coils. Do those that it has happened to leave your bike parked outside? It rains quite a bit in the UK so plenty of water standing/pooling on the bike for days/weeks at a time if the case. Is the Yamaha p/n and coils identical for Euro and NA bikes?

I just changed my plugs again yesterday at 103K miles, not a spec of rust on the coils. I do plenty of water crossings and ride in the rain but my bike is usually garaged at night, Has only stayed outside in the rain maybe 30-40 days in the 3 years I've owned it.

 

[RCinNC]

I had rust on one of the plugs when I changed them last month. My bike has always been stored in a garage, and the only time it's even been outside overnight is at a motel. Even then, the bike had a cover.

I think it's a combination of an imperfect seal on the coil sticks, and water from road spray during rain riding getting up past the cowling. It seeps into the spark plug recess and just lays there, and takes forever to evaporate because it's covered by the coil stick.

When I put the plugs back in this time, I used dielectric boot grease on the coil boots, and a bead of BelRay waterproof grease around the flange on the top of the coil sticks, to improve the seal. The plugs will have to come out sometime this summer for my second valve clearance check, so I'll know then if that method is working to keep the water out.

 

[SilverBullet]

I always find the same plug with heavy corrosion (far right facing bike from front) but never full blown rust and the coil metal is still spotless. I tend to leave plugs in longer than most also. Usually ~30k miles but below photos from yesterday are almost 43k.

So yes water/moisture gets in but never fills up high enough to affect the coils I guess. Sitting outside in an extended day/week downpour without riding could be another story. That water will boil and steam away rather quickly once you start the bike. But sitting without using the bike will not.

I did however put a thin layer of dielectric grease completely around the coils for the first time.

Sent from my SM-G860P using Tapatalk

 

[Moho Miner]

The bike is garaged at home and also when I get to work, but I ride it everyday 70 miles. Its got 35k miles on the clock. The plugs/coils were last out about year and a bit ago - i'm pretty shocked at how bad it is on that plug, but perhaps the rubber seal just totally failed and lots of water got in there. But in the UK and northern EU they use lots of salt on the road in the winter for weeks at a time. The winter has been pretty bad here so perhaps thats made it worse.

Got a self tapping bolt into the the coil and even with the claw of a hammer on the bolt I couldn't remove it - it actually bent the hammer.

I'll certainly be getting some grease in there from now on, never having this again. Defo worth checking every few months in the bad weather.

 

[RCinNC]

My bike never sits for long. I can ride here in NC year round, and the bike doesn't go more than a couple days without being run. Any water in the spark plug well doesn't have much time to sit, but the rusty plug I removed from my engine during the last spark plug maintenance was worse than the one in your photo, Silverbullet; it wasn't just discolored, it was crusty. Plus, if it's hot enough in the spark plug well to boil water, then no water should ever be able to collect there while you're riding that would remain in there long enough to rust the plug; it would be boiling off as soon as it got in there, especially if it was just dripping past an imperfect seal in the coil stick. The only way water could collect in the spark plug well under those circumstances would be if it got into the spark plug well somehow while the engine was cold.

It's possible that water does turn to steam in the plug recess, but the steam keeps condensing and what doesn't escape past the seal on the coil stick drips back into the well and the cycle starts over again. Even under those circumstances, eventually the water would boil away, or else the steam would build up and blow the coil stick off.

My worst plug had the same appearance as steel that's in a perpetually wet environment; not just a patina of rust, but an actual crusty layer. Kind of like a nail that's been sitting out in your yard for a couple winters. That's what makes me wonder if it actually does get hot enough in the spark plug well to boil water. I know that some engine heads get up into the 400 F range or more, at least in some spots, but do the S10 heads get to 212 F or more at the bottom of the well, or anywhere inside the well? I don't know. I just don't think that, if water was boiling away and not collecting in the spark plug wells, there'd never be enough moisture in the spark plug wells to form the kind of rust and corrosion that would actually seize a coil stick in there to the point it couldn't be removed. Water sure seems to be getting inside some of the spark plug wells and remaining there, even when the bike's being ridden just about daily.

 

[stutrump]

For what it's worth. My bike gets ridden every day in all weathers but is always garaged at night and always stays on the main stand (not side stand). It is always plug no.1 that rusts the most. Yes there is lots of rain in uk and lots of surface water on the motorways.

 

[Kiejoe]

I know it's a year later ...! 2012 40k s ten ,water in plug coil area is a pain .....this is second S10 I've had ,live in the lake District Norther England ,bike at mo is waiting for yet another set NGK,s this time plug/coil 3 L/R sitting on bike, last time plug 1 &4 , it's bollocks Yamaha ,to the point I check every month or 1...2 thou MLS ,...this time viton seals on each coil top, then as much hi temp grease as needed ,...were on our tenth consecutive day of rain in the lakes today ,...if the sun damaged Supertens ,mine wouldn't,t get damaged (lol) ...apart from this Achilles heal ,..I love the S10 ,...and luckily I don't mind getting the spanners out ...even the hair driers been over the top those plug wells ...! Untill my mind argued with itself regarding condensation ...hahaha,...oh and the lovely lady in my life asked why they was oil on hairdryer ...errrm ...no idea XX