The jets are tiny little brass screws with small holes in them. To replace the main jets you have to remove the air filter assembly and then remove the top of the carb. Removing the top is a little tricky because of the choke linkage. You can remove a small split pin that holds this in place.
After installing the new jets, I adjusted the timing and then the fuel mixture. I also altered the timing using the timing gun. With the vac on the carb plugged, I set the timing at around 14 BTDC. It doesn't ping (or knock) when I drive, so I assume this is good. Adjusting the idle took a little trial and error, and I may revisit it.
Prior to changing the jets I pulled the spark plugs. They were a little white, which can indicate a lean mixture, so the new jets were probably a good idea. The new plugs are gapped at 0.030.
