Can I use 2006 cbr1000rr gauge on my 2004?
 

I had a problem with moisture getting inside my speedometer. I'm thinking about replacing it. Lemme know what you guys know. Thanks :)

I'm pretty sure you can as it's the same generation
I'd look for the small differences that happened inside that generation, but if it's nothing substantial, I'd go for it.

Look at part #s on bike bandit or ronayers. If they're the same, you're in business