I am a newbie and stuck in coaster brake mentality. I recently purchased a Schwinn Avenue (read inexpensive or cheap) Cycle with Schimano 7 shifter,( yes it came in a box and I assembled it wish I had the video of that). However it run well but, I cannot get it to shift from the small chain ring to the second chain ring (falls just short) it will shift from one to three OK and three to two to one OK. I have tried adjusting the cable tension and also the H L screws but she is just not making the shift. Any suggestions?