I have recently purchased a Specialized Roubaix SL4 Elite Disc carbon frame bicycle - But I am not particularly happy with the colour. It is charcoal and white. I like to have a brighter colour. Is there a way to repaint a carbon frame or at least change the white pin stripe to a bright green. Thank you for your kind contribution.
I'd avoid doing this.
Basically, you do a light (typically wet) sanding by hand (very carefully), prime it with an appropriate primer (maybe a few times) and then paint over it with an appropriate color. However, since the sanding has to be done carefully (since its easy to destroy carbon fiber by sanding), you're going to end up paying someone a lot of money to do this (since it takes a lot of time to prep the frame).
You can't really use chemical strippers or other techniques that you'd apply for aluminum and steel frames can destroy the carbon fiber. You also can't do things like powder coating for the paint step, since you have to heat the frame to the point where the carbon fiber can be destroyed.
If you're really insistent on doing this, there are shops which specialize in repainting carbon fiber. But, they'll charge you an arm and a leg due to the amount of labor they'll have to put in to prep the frame for repainting.
I would agree with batman that you don't want to paint it. Instead, you can think of skinning it with adhesive film. 3M and others sell series of stretchable adhesive films in various colors and textures that are used in the custom automobile and motorbike market.
They should be pliant enough to decorate your bike -- and if applied with care, won't be immediately visible as applied films.
There are companies that will plastic-wrap a car, its cheaper than a paint job and can be removed with no further damage to the skin.
The downside is that if you get a crack in your frame, you won't be able to see it through the plastic wrap, when you do your periodic maintenance.
Consider some coloured riding goggles if you want to change how it looks :-)
Answer: ride it as-is.