find a hardware store that sells jewlers drill bits, take your jet in with you & find the # bit that fits your jet. (probably a #70 bit) Then use the next size bigger to drill the jet. DON'T DRILL IT TOO BIG!!!
After you drill it one size bigger & put it back in the carb and take the bike for a ride.
If it seems to run a little better but not yet perfect then drill it again with the next size up until it runs good. AGAIN!!! DON'T DRILL IT TOO BIG!!!
If it runs worse, then you know you need to make the hole smaller.