Hey,
just wanted to share the newest info on the unofficial Peruvian version of the Death Road of La Paz - the road from Cuzco to Santa Maria/Hidroelectrica and eventually, Machu Picchu.
First off, the road from Cuzco to Santa Maria (the closest village to Machu Picchu accesible by bike) is tricky all year round: because of landslides, waterfalls, springs and streams from the snow-capped mountains and good old negligence, sometimes the road is blocked. Because Peru is, well, Peru, the police sometimes don´t bother to stop you and inform you there´s a roadblock or a bit of a road that´s actually been destroyd completely; there have been numerous bikers having to turn around mid - way simply because the police officers told them to go back in the middle of the road instead of the very beginning of it due to mis-communication or simple laziness. So once you reach Ollantaytambo, it´s a good idea to check with the local police and make them tell you whether the road is accessible.
If however you still get stuck, there are quite a few villages that have hostels with garages for bikes (especially Santa Teresa) as well as gas stations or locals selling gas.
And finally, as you get to Hidroelectrica (the hydro-electric plant), that´s where the road ends. Literally. The only way to get to Machu Picchu is either taking the ridiculously expensive train (USD 50 one way for a 15 minute ride), or hiking (around 7km, but the views are totally worth it). As you reach the Hidroelectrica, there is a tourist check-point sort of post. Ask for the security guards; they will happily watch your bike for 15-20 soles (around USD 9) a night while you make your Machu Picchu hike.
The other thing is, most people stay the night in Aguas Calientes, or the Pueblo Machu Picchu. This is however a horrible, overpriced, stifling, tourist-packed sort of place. I highly recommend staying the night at Jardines de Mandor - a lovely quiet hostel on km 114 along the train tracks to Aguas Calientes. It´s cheap, comfy, quiet, has great food, great trekking if you want to stay a bit longer, the manager speaks good English, and is incredibly helpful. It´s only 2 km from the actual Machu Picchu and around 2,3 km from Aguas Calientes (where you will inevitably have to go just to purchase your Machu Picchu tickets).
cheers