bent spark plug electrode

glider

Just a thought here, did you check the ceramic on the plug like Dan mentioned ?

Could have lost a piece of that which did the damage.

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bikermoses

Well Ive got some bad news it happened to me with a 2 stroke the end of the plug looked like it melted. I had did exhaust and added a K&N filter and had thought we put in the correct jetting,but sadly wide open throttle it was to lean fried rings and was a mess in there. I'm not saying that's what happened to your friends bike but i thought i would share that with you.

mikefxst

sorry i had forgotten about this link. but detonation was actually the cause he had changed out the pipes and never had it re-tuned the electrode was actually melting down from running to lean

glider

How is the heat range of the plug itself. Stock plugs?

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KingHeritage

I wasn't aware that you needed to re-tune with just an air cleaner and exhaust change.Wouldn't the O2 sensors detect a change in air flow and mixture as to have the stock tuner re-tune the engine?The stock tuner must have some capability to self adjust,right?If not how could you ride a stock bike from sea level to the mountains?

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Mattman4403

The O2 sensors are a narrow band. They handle the altitude but not changes in th amount of air brought into the motor. Does sound like something got into the cylinder though. I would get a bore scope in there or just get the head pulled and make sure something was not headed south.

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STEVE07

In our racecar sometimes a plug would close up under extreme axcelleration when the tamperatures were very warm.what temperature was his bike running,and how hard was he playing?

mikefxst

he wasn't running it hard but was running for an hour at least and he had changed the pipes about 2 weeks previous to this happening and yes he was running the stock plugs to answer another question. since the re-map there have been no problems and the bike is running 10 times better.

Bluesugar

OK..Here's what to do to see if anything is left in the cylinder....pull both plugs...Get your wet/dry shop vac,..clean it's tank real good,...adapt some rubber,plastic,surgical,etc...hose to your sucking end of vac that will fit snug in the bikes sparkplug hole and turn motor over several times while vac is running,...you get the idea,...You might be surprised at what winds up in your vacs tank ..or if it's to large to go through the hose it will be at the end of the hose as you pull it out!!...(this proved to be priceless at our 1976 Daytona race)

joel

See if you can get a video scope, I have 1 and used on my bike just to see if any damage was done from a pinging condition I had, did the plug show any signs of contact? in a automotive engine I have seen this be caused by an extreem lean condition causing the neg. electroid to bend do to extreem heat, and with combustion pushing the gap closed. If you know anyone with a inferred machine you could see what the CO% readings are. higher the # the richer the condition. Just a thought

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