cyclist trying to bulk up the top need help

[Liquid30]

I am a collegiate downhill racer, I am trying to bulk up my shoulders, and chest. Being really working on it for about a year. when I first started noticed improvements, but now have plateued. need to get over the hump. It seems like all my gains go straight to my legs from the cardiovascular training from riding. usually will ride 100+ miles a week
I can't use roids, or performace enhancers, because of drug testing for cycling.

anyone have any suggestions

 

[Insane_Man]

What's your routine like right now?

You should start eating more too, although since you're doing 100 miles a week you probably are already eating quite a bit. So that might be hard. But that is where your gains will come from, diet.