The Shell Cycle (literally: "Shell Motorcycle") is a red and black motorbike, mostly used by Raphael. It is first seen in the episode 'Meet Casey Jones' in the 2003 TV Series and continues to be used throughout the series. It is used for making quick getaways to catching villains on the loose. Raphael is shown to be a skilled motorist. It is also used in the 2003 GBA video game.
The Shell Cycle is Raphael's main vehicle. Apart from using the Battle Shell, Raphael uses his cycle for going on missions on his own. It is the perfect vehicle to ride the streets with. The first appearance of the cycle is in 'Meet Casey Jones' where Raph meets someone almost as angry as he is. The two have a brawl out for some time before Casey Jones knocks Raph out and escapes on his motorbike. Casey tells Raph if he wants a rematch, he'll have to meet him in Central Park on Friday. Raph goes to his brothers and tells them everything. They customize the armored truck with all sorts of gadgets, paint and parts. They all get in the Battle Shell and head towards Central Park. The TMNT find him racing towards the park. Donatello tells Raph he 'whipped up something in the back'. Raph checks it out and finds a brand-new, shiny red motorbike complete with helmet. Don said he called it the 'Shell Cycle'. Raph is very happy and says to Don "Donatello, you are the Turtle!". Raph smashes through the Battle Shell's doors and heads towards Casey. It is always kept in the back of the Battle Shell for emergencies. It continues to be very useful in the series. A notable moment was in 'Scion of the Shredder' or 'Prodigal Son' when we see it, Raph tries to escape from the lair by riding the streets in the Battle Shell. However, a Foot helicopter hovers over him and launches two missiles at the vehicle. Raph spots the helicopter and knows he's in trouble. Just before the missiles hit the Battle Shell, unseen by the pilot, Raph grabs his motorbike and hits the doors. He then flees before the Battle Shell is crushed and his cover is blown.
Raphael's motorbike is a motorbike unlike any other. The Shell cycle is basically nothing more than a heavy motorcycle that Donatello specifically designed for Raphael to use. In order to construct it specially to Raphael's needs, it was assembled from various parts of high-performance vehicles. This motorbike is painted bright red, probably to match Raph's bandana. It has a turbo boost to increase speed, effective for catching enemies. Because of Raphael's reckless driving it has been specially designed for stability and could therefore easily endure a heavier rider, such as Hun. It can perform wheelies which make the motorbike go further and faster. It also has some bulk which makes it strong and it can knock off other motorists. The motorbike's braking is perfect when stopping to avoid death at the edge of a cliff. It's small, circular headlights are less brighter than Casey Jones's motorbike but other features make this motorbike solid as a rock. It also seems to have a remote control mode in it as when in 'Meet Casey Jones', Raph jumps off his motorbike and attacks Casey. He glances back and sees the motorbike stop automatically. One of the best motorcycle's in any universe.
A brief description of the vehicle is in Simon & Schuster's - Turtle Tales: An Insider Guide by Leonardo.
The Shell Cycle occurs in the 2003 GBA video game based on the 2003 series.