Spark plug split in half
Road Warrior
Joined: Mar 2014
Posts: 1,623
Likes: 698
From: nowhere
Actually, I have seen this before. It was the early '70's. ( Hurricane Agnes? IIRC.) These plugs had been underwater for a few days and had absorbed some water. As the engine heated up, the water flashed to steam and shattered the porcelain.
Road Warrior
Joined: Dec 2016
Posts: 1,945
Likes: 938
From: Up a tree making meth coolaid
So the brown stuff isn't some lube you slathered on to "prevent corrosion". Guess that leaves the only other logical conclusion to jump to and assume your buying the same junk batch of cracked plugs from the same store. I've heard from folks off and on that rust, when subjected to a heavy zap can make a violent reaction. Cracked porcelain is letting moisture seep into the core, which rusts, then gets a few thousand volt zap, and she pops. My logic may be off base though, can't say for sure.
I would get new plugs (different brand and store) but not OEM. They will hand you champions, they suck. Only plugs I've actually had premature failure on, and I'm not the only one. Any store can give you a plug that cross references to OEM specs. And just to play it safe at this point because they may be compromised as well of replace the plug wires. Plugs and wires are cheap and easy to do. If nothing else you now know it can't be them. And don't use a plug socket, they should thread all the way in by finger and only need a good snugging with an open end wrench. This will let you be nice and careful not to crack them as your fighting the plug socket off.
edit: what Joe ^^^ said makes sense to me also. Is this bike stored outside and uncovered?
I would get new plugs (different brand and store) but not OEM. They will hand you champions, they suck. Only plugs I've actually had premature failure on, and I'm not the only one. Any store can give you a plug that cross references to OEM specs. And just to play it safe at this point because they may be compromised as well of replace the plug wires. Plugs and wires are cheap and easy to do. If nothing else you now know it can't be them. And don't use a plug socket, they should thread all the way in by finger and only need a good snugging with an open end wrench. This will let you be nice and careful not to crack them as your fighting the plug socket off.
edit: what Joe ^^^ said makes sense to me also. Is this bike stored outside and uncovered?
Last edited by J_MOSH; Sep 13, 2018 at 07:16 AM.
Stellar HDF Member
Joined: Sep 2009
Posts: 2,114
Likes: 666
I’ve only seen this a few times. If ignition timing is too far advanced it creates violent spark knock which blows the spark plug apart. If you wrap the spark plug porcelain with a good quality electrical tape it will prevent it from shattering and will tolerate a more detonation than unwrapped.
For the times when the whole sparkplugs get blown out of the heads use red Loctite on your sparkplugs. This will help prevent them from leaving the engine unexpectantly.
Oh, and the brown stuff? I’ll bet that’s poop from the rider absorbing the detonation which creates bowel pressure...usually when least expected.
As always, JMHO,
Bob
For the times when the whole sparkplugs get blown out of the heads use red Loctite on your sparkplugs. This will help prevent them from leaving the engine unexpectantly.
Oh, and the brown stuff? I’ll bet that’s poop from the rider absorbing the detonation which creates bowel pressure...usually when least expected.
As always, JMHO,
Bob
Seasoned HDF Member
Joined: Mar 2010
Posts: 38,593
Likes: 6,435
From: Honah Lee
Mine use to do that on my huge Cumming Diesel with 100-1 compression ratio sled puller. Short of that, you need to get a spark plug socket with the rubber support and after screwing snug with your finger, tweek it with just a little bump or better yet, just use a box wrench. That is ham-fisted mechanical work at it's finest.
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5th Gear
Joined: Sep 2018
Posts: 9
Likes: 0
From: columbus
Yes, it is stored outside uncovered
So the brown stuff isn't some lube you slathered on to "prevent corrosion". Guess that leaves the only other logical conclusion to jump to and assume your buying the same junk batch of cracked plugs from the same store. I've heard from folks off and on that rust, when subjected to a heavy zap can make a violent reaction. Cracked porcelain is letting moisture seep into the core, which rusts, then gets a few thousand volt zap, and she pops. My logic may be off base though, can't say for sure.
I would get new plugs (different brand and store) but not OEM. They will hand you champions, they suck. Only plugs I've actually had premature failure on, and I'm not the only one. Any store can give you a plug that cross references to OEM specs. And just to play it safe at this point because they may be compromised as well of replace the plug wires. Plugs and wires are cheap and easy to do. If nothing else you now know it can't be them. And don't use a plug socket, they should thread all the way in by finger and only need a good snugging with an open end wrench. This will let you be nice and careful not to crack them as your fighting the plug socket off.
edit: what Joe ^^^ said makes sense to me also. Is this bike stored outside and uncovered?
I would get new plugs (different brand and store) but not OEM. They will hand you champions, they suck. Only plugs I've actually had premature failure on, and I'm not the only one. Any store can give you a plug that cross references to OEM specs. And just to play it safe at this point because they may be compromised as well of replace the plug wires. Plugs and wires are cheap and easy to do. If nothing else you now know it can't be them. And don't use a plug socket, they should thread all the way in by finger and only need a good snugging with an open end wrench. This will let you be nice and careful not to crack them as your fighting the plug socket off.
edit: what Joe ^^^ said makes sense to me also. Is this bike stored outside and uncovered?
