Going to a richer main sounds backwards.
Try a leaner main ... Because as engines warm up their fuel to air ratio gets RICHER because warm air is less dense (which means less of it) mixing with the same amount of fuel.
However... You should do a "plug chop" first.... That means getting the engine totally warmed up and running it as fast as it can go for a good half mile or more... then stop on the spot and pull the plug... If it is not going white... then you need a LEANER main jet... and only go 1 step at a time.
And once you put the leaner one in.... do another plug chop.
When you are doing plug chops... It is important that you stop ON THE SPOT from high speed and check the plug color... because idling down and riding at low speed will color the plug.... What you want is the color while the engine while is running wide open.
And for checking the reed valve... put it up to you mouth and try to suck air through it backwards... it should let little (if any) air through.