CBR tacho stopped working randomly

[bigdom86]

Hi All

my 02 cbr f4i tacho and speedo stopped working today on my ride into work, not a massive issue. I have read a few threads and looks like I will need to take apart the front end of the bike quite a bit to get into the circuit board and clean things up (apparently most likely culprit is rusted screws?) - no haynes manual or tools currently, how much of an issue would it be just to ride the bike for the next few months without the tacho or speedo? I am just doing London commuting so don't need to worry too much about speeds

[ThunderGuts]

If the speedo is mechanical, check the cable is connected into the speedo and into the mechanism on the wheel; mine dropped out the back of the speedo recently and killed the speedo. Not sure about the tach though and seems a bit odd that both would go simultaneously. Is your odometer still working?
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TG.

[Nobby the Bastard]

If the speedo and tacho aren't electrical you've been very unlucky to lose both simultaneously.

Working on the principle that it's electrical as a result, the common wiring would be the earthand depending on the deeign, a 12 volt constant power supply.

Check the earth is working first, and then investigate power supplies to the clocks.

You have check that a plug hasn't come loose or a fuse hasn't blown?
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trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Sprint ST 1050

[stinkwheel]

My VFR once did that right before it cut out due to a cooked battery (duff reg/rec) so worth putting a meter over the battery as a precaution.

In 02 honda still had a habit of using flexible PCBs to back their clocks. Corroded tracks are a common fault. This is probably what it is. You'll see it when you get to it (enjoy dismantling your entire motorcycle).

Most bikes wouldn't bother. SOME bikes have the CDI tied into the rev counter (mostly kawasakis) and expect a resistance on the end of it or they won't run. Some grey import japanese bikes have the CDI tied into the speedo and will only run on two if it's disconnected.

The fact it's running normally suggests this isn't an issue with your bike.
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[bigdom86]

getting my odo and tacho mixed up, it was my odometer (distance travelled) and speedometer which both went at the same time - have been riding all week with no issue. looks like a big job taking apart the whole front end to get to it so don't know if I will be bothered to be honest for now, although I do want to sell the bike for something more comfy so might have to just get it done

[ThunderGuts]

[DrDonnyBrago]

Hi, if you have no power to the speedo unit at all then follow other people's responses.

If it is just the speed reading on the speedometer which isn't showing a speed (and consequently the odo/trip counter don't work as it's not measuring speed/distance) but the rest of the speedo unit is working properly (i.e. you have you have the lights, clock, temp etc showing but no speed reading) then it is likely your speed sensor that is on the blink.

Same thing happened to mine years ago, so I wrote a howto. It is DIYable, simple but fiddly. In my case I replaced it with a used unit from a breaker (was about £30 iirc):
https://cbrforum.com/forum/how-mechanical-40/how-f4i-speed-sensor-swap-110034/

[bigdom86]

[DrDonnyBrago]