I'm sorry to say that hero majestic parts or information is just about impossible to get, if I would have known this I may have not purchased this moped, but I have to say it is a very well made moped but if something breaks you may be doomed trying to find a part to fix it. I even went to those india places on the net called alibaba WHAT A JOKE of a place that is, the india guy gave me the run around for 4 weeks I started to suspect it was a scam, he kept telling me I will check for you in the email, I started thinking is this a automated response? All I wanted was spokes I ended up getting them off an old motorcycle, they were slightly larger but fit, you may want to dump that bike if you don't want big headaches but for a stock bike it is very fast. my does 40 + and it's stock or at least I think it is I have no documentation, please let me know if you find anything, I have given up hope, I have a bad carburetor that I need to change.
This is the place I buy parts for my Puch, you can try there for some things that may be standard fit for your Pacer like rims carburetors chains throttles that kind of stuff. Good luck