Quote from: centuryghost on December 03, 2009, 11:45:10 PM
Definitely not "normal" wear. Let's start with the basics; if you can't remember the last time you cleaned or synced yer carbs, do it.
But I digress. Your leftie reminds me of my Jeep's plugs when my head gasket was going south. Less compression=detonation? Help me out here...

Low compression = inefficient combustion = fouling and deposits

Detonation happens when you get an explosion on the compression stroke due to an insufficient octane rating on your fuel.  It explodes much like a diesel.  However, gasoline engines arent designed to be able to withstand the temperatures/pressures caused by said combustion and will usually eat themselves in very short order.  You tend to get detonation in heavily boosted engines and improper fuel choices or using cheap gas in high compression engines.  you can stave off detonation by retarding timing, with the sacrifice of power

that deposit looks funky.  almost like the plug was fouled, then was exposed to a lean condition and then glazed the deposit

All that sounds right to me. 

Let me add that heavy fouling can cause hot spots - piles of carbon buildup krap, that get so hot that they will cause detonation.  So it is possible that the fouling caused the detonation, leading to a spark plug covered with fouled fuel and oil, then coated with melted piston aluminum from predetonation.

I don't think that is really what this is, just an interesting theory.

id say oil is getting in there or that plug is missfiring half the time. i doubt its bad/contaminated gas because both carbs use the same gas so the other plug would be similar. both oil contamination and intermittent misfire can cause plugs to look like that. although severly unsynced carbs could cause that too. first replace both plugs then  sync the carbs asap. then check plugs after a few hundred miles, if the plug in the offending cylinder looks bad again clean/replace plugs as necessary and switch coils around. if the bad plug follows the coil then youve got a bad coil if the bad plug happens in the same cylinder again id bet on oil contamination.

Quote from: centuryghost on December 03, 2009, 11:45:10 PM
Definitely not "normal" wear. Let's start with the basics; if you can't remember the last time you cleaned or synced yer carbs, do it.
But I digress. Your leftie reminds me of my Jeep's plugs when my head gasket was going south. Less compression=detonation? Help me out here...

The carbs are off and appear clean. I removed a slight bit of varnish, that's it. As far as being synced I will need to add that to my to do list.

Quote from: BelfryExpress on December 04, 2009, 12:59:56 PM




Low compression = inefficient combustion = fouling and deposits

Detonation happens when you get an explosion on the compression stroke due to an insufficient octane rating on your fuel.  It explodes much like a diesel.  However, gasoline engines arent designed to be able to withstand the temperatures/pressures caused by said combustion and will usually eat themselves in very short order.  You tend to get detonation in heavily boosted engines and improper fuel choices or using cheap gas in high compression engines.  you can stave off detonation by retarding timing, with the sacrifice of power

that deposit looks funky. almost like the plug was fouled, then was exposed to a lean condition and then glazed the deposit
   

    Given what I think I know about my bike, what you say sounds very plausible > Low compression leading to incomplete combustion of fuels resulting in fouling of the plug which then is glazed on the plug by a lean condition.

The compression was tested during a laymen's motorcycle mechanics class that I took a couple years back and it turned out to be very low. I think I remember the teacher saying that the vacuum was very low but now that I think about it I'm not sure what vaccum has to do with a compression test 
In addition to that, it's very likely my bike has been running lean. After recently taking apart the carbs and checking the jets for the first time since I bought the bike used a couple years ago, I discovered it was running stock jets with one washer underneath each needle and the idle mixture screw had been changed from the factory setting of 2 turns out to 3.5 on one side, 4.5 out on the other (don't recall which side was at which setting). It has an aftermarket OEM size K and N air filter (not the lunchbox) w/o the restrictor. I have a stock exhaust. Given that is has been running with a slightly more open air filter without larger jets I feel I can safely assume that it was running lean, according to what everyone says here on the forum regarding the bike being lean from the factory.

Quote from: BeerGarage on December 04, 2009, 02:52:01 PM
All that sounds right to me. 

Let me add that heavy fouling can cause hot spots - piles of carbon buildup krap, that get so hot that they will cause detonation.  So it is possible that the fouling caused the detonation, leading to a spark plug covered with fouled fuel and oil, then coated with melted piston aluminum from predetonation.

I don't think that is really what this is, just an interesting theory.

I don't know, sounds plausible...

Quote from: black and silver twin on December 04, 2009, 02:58:01 PM
id say oil is getting in there or that plug is missfiring half the time. i doubt its bad/contaminated gas because both carbs use the same gas so the other plug would be similar. both oil contamination and intermittent misfire can cause plugs to look like that. although severly unsynced carbs could cause that too. first replace both plugs then  sync the carbs asap. then check plugs after a few hundred miles, if the plug in the offending cylinder looks bad again clean/replace plugs as necessary and switch coils around. if the bad plug follows the coil then youve got a bad coil if the bad plug happens in the same cylinder again id bet on oil contamination.

What would cause a plug to misfire??

Quote
Quote from: black and silver twin on December 04, 2009, 04:58:01 PM
id say oil is getting in there or that plug is missfiring half the time. i doubt its bad/contaminated gas because both carbs use the same gas so the other plug would be similar. both oil contamination and intermittent misfire can cause plugs to look like that. although severly unsynced carbs could cause that too. first replace both plugs then  sync the carbs asap. then check plugs after a few hundred miles, if the plug in the offending cylinder looks bad again clean/replace plugs as necessary and switch coils around. if the bad plug follows the coil then youve got a bad coil if the bad plug happens in the same cylinder again id bet on oil contamination.

What would cause a plug to misfire??

If the plug gets too fouled from running rich or just being really old or getting a conductive coating from contamination it can either stop the electrical travel through the secondary system of the coil or short out the plug allowing the current to bypass the plug gap and create no spark. also if you have weak coils they can cause a miss, a bad ignition pickup can also cause a miss.

you need to take the carbs apart clean the crud out of them then sync them. if you get another nasty plug switch the coils around. if the bad plug follows one specific coil then that coil/wire is bad. if the same cylinder continues to super foul out plugs then id bet on oil.

buddha, you say additives did this? what is a good amount of fuel stablizer if i fill my tank up for the winter?

Quote from: black and silver twin on December 06, 2009, 09:37:09 PM


If the plug gets too fouled from running rich or just being really old or getting a conductive coating from contamination it can either stop the electrical travel through the secondary system of the coil or short out the plug allowing the current to bypass the plug gap and create no spark. also if you have weak coils they can cause a miss, a bad ignition pickup can also cause a miss.

you need to take the carbs apart clean the crud out of them then sync them. if you get another nasty plug switch the coils around. if the bad plug follows one specific coil then that coil/wire is bad. if the same cylinder continues to super foul out plugs then id bet on oil.

Thanks a lot for the help. It'll be awhile for me to get to doing the different things that you've suggested but it's very helpful to have a better idea of some of the different possible causes of that funky plug. 

Quote from: gregvhen on December 06, 2009, 11:02:29 PM
buddha, you say additives did this? what is a good amount of fuel stablizer if i fill my tank up for the winter?

If it was additives, how did the left one do that and right be different.

I dunno, somehting is off on 1 cyl. I first thought he was detonating, but looks like its not melted, its just some serious crud. That can be just high fuel level or 1 carb got dirtier. Like left carb will likely get more dirt cos its lower when on side stand. But additives, well, they dissolve in the gas and are not going to separate with gravity.

I dunno, maybe just high fuel level. He's just got jets from me, I think he should go over them and set them all equal and see.
Cool.
Buddha.

I'm sticking to my guns here 

Check float height and sync the carbs.

Will do guys, float height check and sync. I'm currently housesitting so it's gonna be a few weeks before I get back to working on the bike.