Electrode Melted on Autolite 4316 plug

[Webbtron]

It was 60° today so I took the 77 Sportster to go to my Sister-in-laws jewelry store (50 miles) to get something for the wife. I lost power about about 40 miles into the ride and was happy to see a rest area sign so I made it there thinking my gap on the points had moved. The gap was ok so I removed the plugs and the rear plugs electrode was mangled looking, kind of like the air was out of it. The top piece and the porcelain at the base of the electrode was not hurt. I bent the top piece over to where the electrode now was and guessed at the gap and it started up. It actually ran pretty good and we made it to an parts store and bought two more plugs. One of which I held in reserve in case it happened again, which it didn’t. I see there was an old 2008 thread about this but I wanted to see if there were any new thoughts. Whatever this can’t be good the plug was tan but not white so to me it was running a bit lean, that jug is usually my richer cylinder. The plugs were new in mid-August

 

[Jack Klarich]

Seems to me Autolite has a warranty on there plugs, I have seen Champions blow the centers out but not an Autolite do this but then again all bets are off now days:s

 

[Webbtron]

Well I used to use Champions all the time but in the 10 years I was out of the picture I guess Champions are now frowned upon so I went with the Autolite & as luck would have it the Autolites was all AutoZone had so I ended up with the same plug again. I was aiming for the Harley shop as I was going right by it but it was closed on Monday's.

 

[NEWHD74FAN]

Champion based HD plugs are priced right and don't know of any problems like those you had with the Autolite ones. Maybe time to go back to the original...? :a

 

[Webbtron]

So you boys think it is a quality product vs a poor quality product. I will take that under advisement. Gosh I thought it was my motorcycle....That old AMF with the electric start they said would be nothing but trouble. Thanks

 

[Hoople]

rear plugs electrode was mangled looking, kind of like the air was out of it.

Wish I really knew what you meant by that. Mangled could mean anything. A picture of the plug would have told a bunch. I have never seen a defective plug "mangled" up its own electrode. I am not saying it is the best plug to use but unless their quality control has gone south,, Autolite is a quality plug.

 

[Webbtron]

Yea I thought about a picture but it is to small so show detail and to tell the truth I don't even know how to do that. But the electrode is listing to one side and has lost it's orginal cylindrical shape. It really looks melted

 

[Hoople]

the electrode is listing to one side and has lost it's orginal cylindrical shape. It really looks melted

Without seeing the plug to learn more, all you can do at this point is run the bike and see what happens next. A '77 bike is pre everything. Pre crank trigger, Pre ECM spark advance control, Pre ION combustion sensing and Pre Knock control. My friends 1979 Sportster is ordinary points & condenser system so my guess is that's what you also have. Lets downshift a few decades with our thinking.

You have a TON of fuel going in the engine by comparison to a post factory stock injection system. I am NOT saying run any plug you have laying around but you do not have to be anywhere as selective as a guy owning a late model bike. It is two different worlds. Hopefully your bike is not so loud that it drowns out the sounds of detonation and you know how to recognize them because you also have no form of knock control.

I would be keeping an eye on the new plugs.

 

[Webbtron]

I wanted to add a bit about the plugs condition. If this was at night I don't know if a guy would have even noticed. One direction it is really obvious but the other way it looks pretty good. I think the key was to bend that top piece back over the top of the disfigured electrode. There is no way I'm hearing a denonation, and I have a Mikuni carb they are not exactly classified "green" pretty much like pouring gas down the throat. Yes on the points and condenser
Thanks Hoople for tying in the technological advancements that is one of the reasons I'm here. Try and catch up in a hurry...I'm still wondering how some of you wash/clean all that "stuff" they got you riding with.

 

[Hoople]

There is no way I'm hearing a denonation,

...meaning your pipes are loud enough to drown out the sound of detonation? With loud pipes and a helmet that covers your ears, it would be very hard if not impossible to detect detonation if it was happening in just 1 cylinder.

I have recorded detonation on my bike when in fact I could Not detect it by ear while wearing a helmet that covered my ears. The early stages of detonation are very hard to hear.