Apologies if this is in the wrong place.
I'm 300lb's or so. I've decided to try cycling to drop some weight and I've bought a used GT Avalanche 1.0 from 2001. It was dirt cheap (or so I thought) but came without a chain. A friend fitted a new one for me and I took it out for my first ride today. When pedalling, the chain (I think) seemed to click and slip a cog or two and I'd feel a bit of a jerk.
Am I too fat for this dodgy old bike? Can it be fixed with adjustments or does it need money spending on a new cassette and chainrings? I have tried to research a bit, but to be honest I'm feeling quite overwhelmed. I haven't ridden a bike in 20 years, lol.