When cold starting my 87 cbr 1000F, the tachometer does not register for 30 sec. to a min. or so, then the needle jumps to the rpm the engine is running at (Electronic tach). What is this an indication of ? Any thoughts out there ?

 

Could be a loose connection. the engine vibrations may be allowing the connection to be made after it runs for a bit.

Could be a weak battery. If the battery is drained too much after the start up, certain electrical components may not work until the battery recovers.

Also (rare), sometimes wires themselves become weak or corroded internally. They require a voltage running through them for a short period of time before the voltage actually makes it through the wire and into the tach.

If you raise the rpms a little, does the tach restore itself quicker? or is it always the same amount of time no matter what?

 

I figured he'd get the most help here in the 1KF section. I'm not too familiar with the operation of the Tach on this year.

 

I have clean and coated all the connections. the battery could be the reason, since it recently left me stranded with a low charge and it does not seem to hold a full charge (off a charger). I will have to keep an eye on it with a new battery.

Also an increase in engine speed does not instantly register a reading.
Thanks!

 

There are two connectors behind the right side of the windscreen area.
Remove the radiator cover panel and see if you can see them - may have to partially remove the clock surround to get to them - there's a wire (I think black and yellow) which is a specific tach wire - may be loose, or the connectors on the loom may not be making proper contact.