I pulled my dads 1983 250R out of an old farm shed the other day got new tires air filter gas fuel line brake fluid its all serviced... However after 2 or so hours of riding in the river it begins to bog out on my as if its not getting one of air fuel or spark so because i know its getting air and fuel i checked the plug it was dry black residue i replaced the spark plug and it ran fine for another 2 hours or so then it went to hell again so I need to know why the plug is becoming this way so fast im running 20:1 which is what it says to run on the gas tank is the air to fuel mixture out of whack? How do i change the air to fuel mixture? don't know what else to do need detailed helpHonda ATC 250R Boggs out after 2 hours of riding.?
20 to 1 is too rich, and you are dry fouling the plug, mix at 40 to 1 and you should be good, todays oil is far better than the 2 stroke oil in 1983
