[Grey Area]

Hi guys,

Could someone please advise me on this little problem which has just started on my tacho.

Previously I had no problems with the tacho apart from the occasional twitchiness when changing up through the gears. Now when I start the bike up the tacho moves up to the normal tick over value 12-1500 rpm but as soon as I rev the engine above that amount the indicator drops off to zero and doesnt budge till the revs drop back to tick over.

This happens when the bike is stationary, or moving and in all gears.

I'm not sure if its a connection problem at the dash or if its a sensor problem (my Haynes manual doesn't really cover this problem).

Am I right in thinking that the rev counter is an electronic sensor within the gearbox and if this is the problem is it field replacable or does it mean an expensive trip to my local mechanic.

Any advice or suggestions would be greatly appreciated

[ghbzorro]

If I am not mistaken, the tach is driven by the ignition control module. If the bike runs the module should be OK. That suggests a poor connection is the root cause.

If I were you I would go over every single connection. It will be a PITA but should eliminate the problem.

[Grey Area]

Thanks for the info,

ICU seems to be working fine, continuity is ok through the loom to the cluster connection. It's also ok through the connector to the cluster itself and through to the screw link connecting into the tacho. (The plastic wiring film was replaced last year with a new one and continuity is fine across the TGM circuit).

Dismantled cluster and examined tach, inside appears ok, no apparent damage to indicator finger workings (the little copper coil that makes it move behind the dial) and the circuit board does not appear to be damaged or burnt indicating shorting.

Local mechanic said if ICU knackered then bike wouldnt go (obviously) so am stuck now. I did find this on an American bike forum

Honda F3 - Bad ICM or Tachometer - South Bay Riders

describing a similar problem so it may just be a dodgy tacho, unfortunately am stuck now as will need a spare cluster to check.

If anyone is in the Merseyside area and has one I can borrow while my bike is in bits for the next week or so (june 18th to june 30th) I'd be most grateful if you could drop me a line

Lee

[WyoJames]

Happened on my old nighthawk but I don't use the tachs on my bikes anyways so I didn't worry about it, then one day I hit a bump and it started working again. I know my story offers no advice at all, but i'm a post whore and I don't care

[Grey Area]

Bought 2hd cluster from Ebay, worked fine, looks like it was a dodgy tacho all along

Ho hum