Spark Plugs

Tom in SW VA

Tom in SW VA

Well-known member
Other than the Champion X plug, what spark plug have you had most success with? I'm using Autolite 66 and am not real happy.


Thanks.....
 
"Not real happy" is way to subjective to be able to give a good answer. How worn is the engine? What seems wrong? Give us at least that.
 
J Franklin said:
"Not real happy" is way to subjective to be able to give a good answer. How worn is the engine? What seems wrong? Give us at least that.
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Thanks for your reply. The plugs that I am using (Autolite 66 with adapters) are fouling (black) terribly. I have checked the compression and it is good. I have changed the gap to .035 from .025. If I clean the plugs after every ride, it runs well. If not, it misses. The engine has a high compression head with the regular electronics; magneto, commentator, coils, etc.


I am just searching a solution. I am a fairly new with Ts. I am quite familiar with As.


Tom
 
If it's oily black, it is from burning oil-worn out rings most likely. If it is dry black it is running way too rich, which means carburetor is bad.
Generally when plugs are fouling, a larger plug gap is better because a higher voltage is needed to jump the gap, which helps burn off deposits.
 
could a worn cam or standard grind 250 have similar dry black deposits with a high compression head installed due to poor or not enough valve opening with that head configuration?

I ask because I have an older high comp head and thought it would be better paired up with a 280 grind cam, any input would be great.
 
Try a hotter plug and try to adjust the carb for a leaner burn if you can. I think the X plug works well and looks correct. Do the adaptors allow the tip of the plug you use to enter the combustion chamber?
 
I run the new style Champion X plugs on 5 different T's. They are gapped at .025" and clean them once a year whether they need it or not.
 
Their turning black for a reason. (really ?). Usually only 2 things as stated above: oil or running rich. Are you blowing smoke and if so what color is it? Blue is oil black is running rich/fuel. You say the comp is OK. I'd like to see some numbers. In my book 45 or better is OK and would make oil burning (worn rings) a lot less likely. What year & what carb are you running? Going with an incorrect needle valve adjustment here because it happened to me in my early T days. Sooted the plugs up so badly it wouldn't run. Being new to T's at the time I couldn't imagine this happening and couldn't figure out why it wouldn't run. When pulling the plugs for a comp test (out of desperation) I found the problem. As to the plugs: changing to another brand won't solve your problem as something else is going on to cause the coating. Adaptors work as do X plugs in a properly running motor.
 
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