sparkplug fouling

[hazmat]

i rebuilt my topend and changed the cylinder and piston. when i was pouring a couple drops of oil on the piston i dropped my oil and it spilled inside the crank case so i took apart and put upside down and used compressed air to clear out now every time i take the bike out i get 5 mins in and the spark plug fouls so i change it and ride same thing this is the 4th time this has happend what should i do i already took out electrical sanded engine block for contact removed extra power wire from magneto redid the boot and cdi connection what else is there

if someone can help this poor engine before i take it out back to shoot it will help me alot

 

[Chainlube]

Will it still run when the plug fouls? You might have to run it some to get the oil to clear out totally.

 

[hazmat]

Will it still run when the plug fouls? You might have to run it some to get the oil to clear out totally.

when the plug fouls its iffy runs cuts out runs cuts out misses alot just really faulty and unpredictable just got back from a ride and smoke seems to be coming off the head so i think your right as far as running it to burn out all the oil thanks chainlube