Cambodia forum

Dear Gill,

I know that I am a little bit late to answer your question, but there might be some other travelers how might ask the same question in the future.

Small bikes like 100cc to 125cc street bikes, you can find plenty of them at road no6 east (highway to Phnom Penh). Prices vary, but you can get a decent Honda Dream for roughly 500-600$ with plate number and registration papers, make sure tax has been paid (2011 sticker blue color).
Dirt bikes 250cc are hard to find. Go to see the white board at Angkor Market, there might be some on sale. Else check with Mr. Rong (No.1 mechanic in town) +855 77 36 7790 (do not contact Hidden Cambodia as it is a rip-off place and bikes are complete crap). Prices go from 1200-2500$ including plate number, registration and tax.
For Siem Reap , you CAN'T rent motor bikes, mission impossible unless you have some very good contacts. If the police is going to catch you in Angkor Wat or in the city, you are going to pay a 400$ penalty. If you want to buy a bike, travel down to Phnom Penh, Lucky Lucky at Monivong Blvd., TheBikeShop or at TwoWheels.
Second, most people forget, that they do not know all the hidden trails, special places with no tourists, nor are there indicated on any maps to ride off the remote places or to discover the countryside. Hundred of thousands of unmarked landmines scattered all around Cambodia also in the vicinity of Siem Reap city. Best to enjoy a ride with a small bike or a dirt bike to check with khmerways.com - in the end just an experienced guide will make your ride memorable.

Jordan