No problem, always glad to help.
Give a man a fish and he eats for a day. Teach him to fish, he eats forever. Here are some videos and comments that will help.
Vacuum leak check
Link to original page on YouTube.
Spark plug fire check. Remember your looking for a BLUE spark, when in doubt change it. Plugs are cheap.
Link to original page on YouTube.
The air box and air filter checks are visual inspections. Although on a pregen, you might need the flashlight to see everything clearly in the air box.
I have a ghetto way of testing petcocks but is simple. Turn the petcock off and remove the line. If it leaks gas, fix it. With the hose still off, turn the petcock to prime, if you don't have a solid flow of gas, fix it. Turn the petcock off and reinstall line. Next drain the float bowls on the carbs (leave drain screw loose). Turn petcock to ON. and try to start the bike. If the petcock working the bowls will start to fill ONLY when the engine is turned over. If the gas does no stop when not cranking the engine, fix it. This is an area you want to pay special attention. If the petcock is getting weak vacuum, it may limit the amount of gas your getting for idle. In 20 years of riding, I have only ever had 1 petcock go bad, if you take the time to clean them ever now and then, they should treat you well.
Other good stuff. MatthewMCRepair (no affiliation) does a series of bike repair and diag vids. Browse through his vids most are very good.
Also, there is EricTheCar guy (no affiliation). His youtube channel is full of great videos for diagnosing odd stuff, suspension noises, performance issues and what not. Most of his vids are about cars, but when I work on bikes I apply alot of the same diag methods he does. Honestly, it's just plain common sense stuff.
Good luck and lemme know if you need anything else.