plug fouls out

[red bandit]

83 Honda ATC Big Red 200. Runs and drives great for about 5 minutes then dies. Take the plug out, moist but not soaked, not sooty and wire brush it, runs great for about 5 minutes. Tryed several new NGK plugs that are correct for bike. You can do this all day long. Cleaned the tank, wasn't bad, very little rust. Fresh gas. Cleaned the carb. New battery fully charged before put in bike. Weak coil? Ideas?

[CaptonZap]

Take the fuel line off of the carb, and put the end into a gallon jug. Turn on the petcock, and if it is vacuum driven, apply vacuum to the vacuum hose. Let it drain. Does the flow slow down after a minute or two? If it drains a gallon without slowing down, replace everything and look else where, such as a blocked vent in the gas cap.
Next culprit to look at is the ignition. Coils can open up, (quit working), when they get hot. Take a wet rag and wrap it around the coil, and keeping it wet, see if the time taken to failure changes. If so, borrow a coil and swap it out and check the other machine for the same failure mode.
And thats all I have to suggest, others will come up with other things to check, we all love a mystery. CZ

[red bandit]

Good idea. I think I ruled out gas but since the bike is out of state and it's been a while since I did anything to it I will try that. I will be visiting the bike again in a few weeks. Thanks and keep the ideas coming.