O.K. ;

FWIW , those # 62 main jets were considered " break in " jets and were supposed to be changed out at the first oil change .

The Phenolic insulator is really important ~ one side has a gasket that faces the intake manifold , the other side is smooth and faces the carby flange with it's O-Ring .

Get a dental pick or whatnot and *carefully* pry out the O-Ring & set it aside .

Now take your BIG & wide fine file , lay it on your knee and run the carby's flange across it , once ~ now look at the flange , it'll prolly have shiny spots only on the very outer edges of the flange , if so , gently run it back and forth across the file only until it's shiny all the way across ~ the carby is made of super soft pot metal so it'll true up very quickly , DO NOT overdo it here else you'll ruin the carby ! .

Also : DO NOT run the file across the carby , hold the file still as you gently work the carby against it ~ this means taking it off the Moto .

Once you see shiny all across the flange , STOP and blow it clean , flip the O-Ring over so the flat surface faces the groove in the carby and re - install it , re assemble being very careful to use 6 MM flat washers and not over tighten it as this is what causes the pesky vacuum leaks .

NO RTV is EVER necessary here ! .

Remember to use a File Card or wire brush to clean the file before putting it up .