It is very difficult to ride the mini dirt bikes and if you are riding the bike for the first time you certainly get some injuries. It will take some months to find out the reason for frequent slips and it will take some years to master the dirt bikes. There are various models of mini bikes from vintage bikes to modern 150cc. The modern 150cc mini bike is east to find but the vintage bike is hard to find because it was the popular model in early 50s. Here are the tips of places where you can acquire the vintage bikes.
You can find the minis in the junk shops and old vehicle graveyards. From 50s to 80s owning the vintage bike is the biggest treasure for motorbike lovers. Still many people motorbike collectors are collecting the parts of the old model bikes and vintage mini is one among them.
You visit the old vehicle graveyards and check with the caretaker whether he or she have any old model vintage bikes in the inventory room or vintage bike acquired through commission might be in some corner of the graveyard accumulating dust.
If the bike is available in the shop then you have to check it in the inventory garage which is around 1000 to 2000 square feet. Most of the inventory garages might be messy and you have to search hard to find the bike.
You can also check with the vehicle museum and private collectors. Sometimes the vintage bike will not be kept in the display items in the museum. Sometimes the bike you are looking for might not be available in the display, you can check with the collector about the bikes which are not at display and if available buy the bike after bargaining the price.
You can search in internet for vintage bikes and post ads if possible and you will get good response from the sellers. Ensure that the bike is in good condition before making the purchase.