Rev Counter not working

[uksurfer]

Went out last night on bike, started it to come back and the rev counter has stopped working,

1) is it fused?
2) what to check? if not fused?

and i got a little hole in the exhaust by the engine mounting bolt!!!!
what a p**ser with the weekender coming.......

not happy!

[analogue_rogue]

what bike is it on?

[uksurfer]

its on a S4, no cable!

[Albie]

First thing I would check is the connections. The clocks have a main connector with a twist plug.

No idea where the rev counter takes off from but could be off the ecu. The s4 has built in coils in the sparkplug caps so they wont come off the coils .

Just check all the connectors around the engine. Im sure it would say in the workshop manual I gave you.


Wheres the hole !!!! by the engine mount or do you mean the exhaust to engine mount point at bottom near the brake lever. Has it just split ???

[Nickj]

The signal for the tacho might come from the ECU, possibly its from the databus wire BUT I think it probably gets it feed from the grey wire that feeds the horizontal cylinder coil.
Was it doing anything odd before it stopped working? Odd twitches, incomplete sweeps??
Which gives you two choices, either a simple wiring fault, the speedo wiper is worn out or the ecu's not well. Of these its probably one of the fist two.

[Scotty]

which year S4 ?

[gregski]

On my 620ie when my rev counter stop working I check every connection but it turns out that there was a damage on the clocks and it's a quite expensive job :worried: and I just left it

Good luck with yours

[rac3r]

As someone said 'A rev counter is just to keep you entertained at the lights'

[Albie]

which year S4 ?

03 plate but probs manufactured 01/02 not sweeping clocks and cable speedo drive

[Nickj]

If it isn't a cable drive then it's often the stepper motor that drives the dial

[analogue_rogue]

If it isn't a cable drive then it's often the stepper motor that drives the dial

stepper motors control idle.. they dont have a feed to the rev count or ecu. the rev count will be fed by the ecu which will take its feed either from a hall effect sensor on a camshaft or on a coil somewhere

[Scotty]

humm the old style clocks eh , I had bother with mine once, the signal is sent from the ECU. I would check the electrical connection inside the clcok houseing

[Capo]

stepper motors control idle.. they dont have a feed to the rev count or ecu. the rev count will be fed by the ecu which will take its feed either from a hall effect sensor on a camshaft or on a coil somewhere

Last time I had one to bits (last week in fact) there was a stepper motor on both the speedo and tach that drives the needles.

[analogue_rogue]

thats a drive motor though, it sets the needle it doesnt send an input. it just works on a variable voltage received from the ecu which converts the digital signal from the pickup. i have never heard it refered to as a stepper motor before.. (could just be an area thing)

[uksurfer]

just got back from the garage, the rev counter was working without the lights on, but with the lights on there was no rev counter, seems as if the rectifier is broken and not putting out enough volts to charge the battery!
So a new rectifier is on putting out 13.5-14 volts, and the old one about 11.5 volts.
Fingers crossed it will be ok, and the new battery i put on last month might be useless now, so i good second hand one might be used!
Bikes stayed at the garage for the exhaust welding where the bracket is attached by the engine mount!
Happy days

Thanks for all your replies :ukm:

[Capo]

thats a drive motor though, it sets the needle it doesnt send an input. it just works on a variable voltage received from the ecu which converts the digital signal from the pickup. i have never heard it refered to as a stepper motor before.. (could just be an area thing)

Trust me they are digital stepper motors, the inputs from the ECU go to the main processor chip, I'm about half way though drawing the circuit board diagram.

The ECU gets the engine speed from the hall effect transducer on the crankcase which reads the cam gear this signal is also used by the ECU for fuel mapping.

The speedo is also driven by a hall effect transducer which reads the rear wheel speed, the signal is sent to the ECU.

[analogue_rogue]

Trust me they are digital stepper motors, the inputs from the ECU go to the main processor chip, I'm about half way though drawing the circuit board diagram.

The ECU gets the engine speed from the hall effect transducer on the crankcase which reads the cam gear this signal is also used by the ECU for fuel mapping.

The speedo is also driven by a hall effect transducer which reads the rear wheel speed, the signal is sent to the ECU.

fair enough dude.. its just all through college they were never called that.. but that was a long time ago and im not up to date on internal workings of clock heads!

[gary tompkins]

http://www.electronics-tutorials.ws/io/io_7.html

http://www.demon-tweeks.co.uk/Performance/Gauges_&_Dial_Kits/Tachometers/SPA_Design_80mm_Classic_Tachometer/817/1459

If R/R unit's only putting out 11.5V it's fooked

Also possibly why battery has struggled to hold a charge - Hence bumpstart at Brooklands in March

[chris yeatman]

http://www.electronics-tutorials.ws/io/io_7.html

http://www.demon-tweeks.co.uk/Performance/Gauges_&_Dial_Kits/Tachometers/SPA_Design_80mm_Classic_Tachometer/817/1459

If R/R unit's only putting out 11.5V it's fooked

Also possibly why battery has struggled to hold a charge - Hence bumpstart at Brooklands in March

wen new battery was put on after brooklands, charge rate was checked my me @ 14v.

[chris yeatman]

i think a good charge up on that battery u got martin then it should be ok.

[uksurfer]

i was thinking about Brooklands problem being related, fingers crossed all good now!

[analogue_rogue]

http://www.electronics-tutorials.ws/io/io_7.html

http://www.demon-tweeks.co.uk/Performance/Gauges_&_Dial_Kits/Tachometers/SPA_Design_80mm_Classic_Tachometer/817/1459

If R/R unit's only putting out 11.5V it's fooked

Also possibly why battery has struggled to hold a charge - Hence bumpstart at Brooklands in March

yeah im pretty sure they were never in my city and guilds in 1995 but hey you learn something new every day.. cheers it made for a good read :D

[uksurfer]

bikes back in working order!
just need fuel and to put the tank bag on, and chill out tonight with a few beers :biggrin:

[weimeranerman]

Interesting and timely thread. I just got back from work and as I was parking up, at idle my S4 rev counter went to zero. It would move normally when blipped but at idle just went down to zero again. Also, the last 10 miles home the bike felt as though it was running slightly rough. Also noticed that my brake light was not working when using the front brake. Any clues?

[uksurfer]

mine was similar, if i put the lights on there was no rev counter, turn the lights off and the rev counter would work, not on idle, only when revving at about 2k
hope that helps

[weimeranerman]

Hi Martin - Just to be certain, was the solution to your problem a new rectifier?

I charged my battery and then started it and all seemed fine. The next morning I went to start it and ran the battery down pretty quickly and failed to start the bike! Battery is only 7 months old and seemed in good nick. Any guidance on how to check rectifier output?

[uksurfer]

i believe theres two plugs coming out of the rectifier, the yellow ones are going in and the red ones are coming out to the battery, my red wires were showing about 11-11.5 volts, the new rectifier is showing 13.5-14 ish, enough to charge the battery.
i think the yellow wires going in were showing something like about 18 v, which is the power from alternator.

Hope that helps but i'm no sparky.........

i took the bike to the garage and i'm only relaying what i remember, i'm sure someone else will know more about them!

[Capo]

A description of the charging

http://www.ukmonster.co.uk/monster/showthread.php?t=36418&highlight=charging

[weimeranerman]

A description of the charging

http://www.ukmonster.co.uk/monster/showthread.php?t=36418&highlight=charging

Thanks Capo. The friendly AA man called around to get the bike started and checked the charging with me as I could not get the bike to start and guess what................ charging at tickover -negligible, at 4000rpm 12.3. He agreed it is probably the RR.

So now to get a replacement! Any recommendations?