yes but dont worry
it just means u need to do a basic sevice every now and again and the bike engine probs wont run at its best for as long also there is no reason why u cant get a dirt bike engine
u dont have to buy from that shop
it may be less conveniant but u can look on ebay and craigs list for a good bike
some people in the local buggy club have shipped bikes from the USA to get a good deal
really an industrial engine will run without a service for years
my uncle has a 1960 8hp stroke deisel water pump hand crank and all smaokes like u will never beleive and sounds like it is running at about 80rpm
this thing runs all day for half the year
he never touches it runs fine