A 2007 with a 2001 motor? Do you know the history of the quad? Check the air filter and see if it needs cleaning. Check the spark plug and clean or replace if needed. Whenever I have bought used machines in the past, I have always changed all of the fluids. This includes draining and flushing the fuel tank and if it had a carburetor, I would rebuild it. Try the preceding first because it is really easy to do. If this doesn't solve your problem, then you will want to check your compression. I do not believe the 01 has electric start. Is it really easy to kick over, or does it feel really loose? Let us know how it goes.