Go to the link below and answer the questions.
Such as type of GPS unit, year, make and model of motorcycle.
http://www.ram-mount.com/Products/MotorcycleMounts/tabid/128/Default.aspx
For example; I have a Garmin Nuvi 1250 and a 2009 WR250R (have to subsitute with YZ250)
Answer;
Part ID: RAM-HOL-GA33U
Description:
UNPACKAGED RAM HIGH STRENGTH COMPOSITE CRADLE FOR THE GARMIN NUVI 1200, 1250 & 1260T $9.22
Part ID: RAM-B-149ZU
Description:
UNPACKAGED RAM MOTORCYCLE HANDLEBAR MOUNT, ACCOMMODATES RAILS .50" TO 1.25" IN DIAMETER $30.21
Has worked like a charm for me. Easy to mount, stable and secure. Gets the unit up there for a great view and the GPS is a heck of a lot more accurate than the speedometer.