The Puller you need for most all of the enduros (except the electric start 125 models) is the M27X1.0 Left Hand External Thread puller. There are many brands, but it is a really good idea to go with a name brand if you can - we have seen some quality control issues on the threads of some of the No-Name ones. Motion Pro makes a really nice one - Model 08-0026 which can be had online for about $15.
Many dealers will stock this. If your Yamaha dealer does not, try a Honda shop as the same puller is used on all of the horizontal 50-70cc Honda motors.
They look like this:
