Testing the bike around the block I noticed on the left side shifter (of a 21 gear bike) when running the #1 small gear the chain won't shift up to the middle gear when you click the grip up into the #2 detent. To get the chain up you have to nudge the grip halfway to #3. Or you can shift all the way to #3 and then back down to #2.

Is this something I could take on myself?