Okay, I bought an 01 CBR 600 F4i today, love the bike thus far, only problem I am having is that the gauge cluster only works when I press the rear break... Do I just need to reground the cluster, or what would cause this?

 

Hmm. Interesting. The ground wire for the cluser is green (as with most of the electronics on your bike) Sounds to me like a power circuit problem though. If you download the service manual there is a wiring diagram

 

Wow, this sounds interesting. I'm stumped.

 

If you have a multimeter, check your power wire at the gauges(with ground test lead directly to the battery)
then do the same for your ground wire with power wire direct at battery. this is all with the bike on(doesnt need to be running, but one starter switch press away from running)

lets see what that turns up! If thats good ill think of something else, but that is weird..lol

 

you know off the top of your head what color the power wire is?

 

Wire that looks like christmas is your power wire. Black brown is your ignition wire(+).

Check voltage of all, then check resistance of them as well.(continuity)

 

Okay, I checked the power on the IGN, Illum and Batt.
There are all with negative on the battery negative like stated.
My battery was at 12.6 before testing fyi

IGN with brake not pressed:0.02
Illum with brake not pressed:0.02
Batt with brake not pressed:12.4

Okay now with the brake pressed
IGN:7.4
Illum:7.4
Batt:12.4

So is it just getting a good ground when brake is pressed? Or is the 0.02volts not even enough to worry about and it is just drawing power off the brake?

 

You've checked all the fuses?

Check the power dist circuits (make sure the bottom of the fuse box doesn't have anything melted)

Follow the rear brake switch wires back to the nearest harness. This one also shares connections from both sets of circuits. Look for anything melted or corroded there.

The numbers you posted make me think a bad fuse on the inst. cluster circuit and a bad ground on the brake light circuit. That doesn't seem very likely to me though it is possible. Check those and report back!