Digital speedometer...How to fix it?

[5v3d3b0]

My speedometer is a digital one on a yamaha tzr 2005. When I had my battery uncharged and I had to push start, the speedometer was distorted...It said i was going 50 mph when really I was doing 30, and when I braked, it thought I was accelerating etc. Sometimes it'd just show 0, and not count any new miles, and sometimes it's be ok. One day it just stopped working completely. (showing 0, all lit up, but not counting speed or miles.) It's still like that after changing the battery.
What could the problem be? Please help me. I need to sell this bike, and it is impossible if the speedo doesn't work.
Also my break light is on all the time. Could this be some rust accumulated on the brake sensor?

[THCi]

Hmm, sounds like a knackered loom.

Tried the budget bodge of spraying in some WD40 into the contacts on the speedo? Also, the problem could be a knackered sensor.

As for brake light being constantly on. There are three places that immediately spring to mind, front reservoir sensor, rear pedel sensor and connections on the actual bulb.


And, are you sure that it isnt the fillament in the bulb thats responsible for the brake part of the light being borked?
____________________
Past: GZ 125 K4 Marauder, VL 125 LC Intruder, FZS 600 Fazer. Present: GSF 600 N K3 Bandit, GSX-R 600 X(soon)
"We're not gonna die. We can't die, Bendis. You know why? Because we are so...very...pretty. We are just too pretty for God to let us die."

[Arfdog]

When you push start such a thing without a battery connected (or a battery that is damaged and has high internal resistance), the alternator can generate high voltage spikes which ar usually clamped to under 20V by the battery. These unclamped, can spike up to around 100V. Such spikes will damage a poorly designed digital electronic system.

Sound to me like a knackered control box or sensor. I suspect you'll be looking at replacing a black box somewhere on the bike, that contains this circuitry.
____________________
I'm a lover, not a fighter.

[5v3d3b0]

How would I get to the sensors for the bulb? What would I have to do to clean it up? where are the contacts of the speedo?
I am a complete newbie to this, and there are no manuals on the internet, not even for sale. Ill put up some pics of the speedo and whatever i think could be useful later if you need them to help me...

[5v3d3b0]

Ok I was checking the bulb, and its the rear brake sensor...Basically when i press the brake, and a rod gets disconnected cutting the circuit. That rod is never actually touching. I have so like press the sensor on its back to get it closer to the rod so it touches it. I could just stick something in between the frame and the sensor to "fix" it, but what is the proper way to go?

[5v3d3b0]

Please...

[THCi]

Best way to go is replace the sensor. Or just sell the bike as seen, but make any potential buyer aware of the problems.
____________________
Past: GZ 125 K4 Marauder, VL 125 LC Intruder, FZS 600 Fazer. Present: GSF 600 N K3 Bandit, GSX-R 600 X(soon)
"We're not gonna die. We can't die, Bendis. You know why? Because we are so...very...pretty. We are just too pretty for God to let us die."

[finpos]

Is the body of the brake light switch threaded? Often they act like a big screw which you turn to adjust the distance of the sensor to the brake lever itself.

finpos.

[5v3d3b0]

YES. It is threaded, but I can't move it around because the actual cable prevents me from being able to turn it...Can I like completely disconnect it?

[finpos]

The cable should unplug from the top of the switch. Sometimes it will just pull off, sometimes there's a little catch on the plug you need to press in first. Should be easy enough to do.

Also look out for a locking ring on the switch body that you need to back off first. It could be the locking ring that is stopping it from turning. Obviously, tighten up this ring after you make this adjustment.

finpos.

[5v3d3b0]

Thanks I'll try it tomorrow

[5v3d3b0]

I fixed the brake light today! YAY. There was this space where the sensor was being pushed into, and I literally rolled up a tiny piece of paper and stuck it in there! It works perfectly, and I know it wont brake for quite a while, and a replacing it isn't exactly expensive
............ ____ xxxxx
Sensor |hole| plastic
............|___| xxxxx
The paper goes in the hole preventing the sensor from moving away when the brake pushes on it upon release. Before that it's go all the way to the plastic. The paper is compressed enough not to get cut apart.