I have An 1978 Puch MK2, and I would like to fix it up... It starts and runs but the top speed is 20 mph, I do not have an air box on it so when ever I run it I cover up the air breather with a finger... do you think If i'll buy an after market air filter (round one) it would be better or it needs an original air box? Second question is, what if I have 6,000 miles on my Puch is this alot? what are the parts need to be replaced to refresh the moped? Does anybody know good sites on Internet that sell cheap parts for Puch? How about if my gas tank is so rusty what can I do to clean it out ? If you know some answers for my Questions please answer.