If it's a 7 speed, it's likely a Birdy Green from the late 1990's .. original Birdy Greens came with belt drive, but later changed to chain .. looking at the picture of your bike from the c/l ad, the stem is on backwards, which might make you feel cramped riding.. The rear elastomer (shock) generally doesn't have a spring.. there are different elastomers with different durometer readings to accommodate different weight riders.. cool bikes.. I've had a few through the years..