New forum member from the UK

[34058]

Hello there.  A quick introduction to myself:  David.  I live near Guildford in the south east of England.  I joined the forum on June 03, 2016 to search for answers to various problems with my bike.

A quick introduction to my bike: a 1988 K100RS in red.  Bought about 7 years ago from a friend who bought it new.  He only did 11,000 miles on it in all the time he owned it.  I have now got it up to 22,000 miles.  So it's barely run in.  It did need a bit of recommissioning, but now it's mostly OK. 

Here is a summary of the current problem I have been having:

I have been searching this (and other forums  ) for a while now because the bike has been suffering from the 'known' speedo problem, on and off, for about three years.  I cleaned up the three pins in the speedo head on five occasions, and even went so far as to remove the PCB that they slot into, resolder all the connections and clean the two additional pin connections on the PCB.  Still no joy.  I also tried a second hand final drive transducer, but lately the speedo needle has only given a vague flick when the bike moves off, then nothing.

So I phoned a motorcycle electrician who had a quick look at the wiring diagram and suggested disconnecting the wire going to the indicator/flasher relay.  It is pin 21 on the instrument cluster wiring harness, and it is there so that the indicator self cancelling monitor can do its job.  I'm very happy to say that this seems to have fixed the problem.  I went on a 15 mile ride on fast, slow, smooth and bumpy roads and the speedo worked faultlessly.

Has anyone else come across this fault?  I have not seen it mentioned or suggested in all the posts I have searched.

That's all for now.  Enjoy your riding.

David.

[The Mighty Gryphon]

Dang!  Who'da thought the self-cancel on the turn signals would mess up the speedometer? 

Welcome! 

[daveson]

Welcome David.

Thanks for sharing that.

Practical results like this are so much easier to grasp and remember than theorising about removing this wire or that wire.

One post in four years, I recon you have some more gems like this one tucked away.

Regards, David.

[34058]

Hi.  Thanks for the welcome.

Now that lockdown is easing up I have booked a trip to that exotic, far away holiday island, The Isle of Wight!   It's a 55 mile blast down the A3 to Portsmouth this coming Thursday evening to catch the ferry, with Mrs 34058 on the back.  We're staying with friends on the island for a couple of days, then coming home.

I'm keeping my fingers crossed that the speedo will behave.  I will post an update here when we get back.

Previous problems have included a hard to trace misfire.  It only played up on cold days with high relative humidity, but not raining, when the engine had reached running temperature.  I finally traced it to the HT leads breaking down.  I found this out after pressure washing the bike to get the winter road salt off.  After giving the engine a good power wash I barely got home.  I was quite surprised that this was the problem, given how well the HT leads are protected.  A new set of leads cured the problem and its been fine ever since.

David

[Laitch]

After giving the engine a good power wash I barely got home.  I was quite surprised that this was the problem, given how well the HT leads are protected.  A new set of leads cured the problem and its been fine ever since.

Considering your use of a powerwasher, that might explain the problem with the speedo. The signal self-cancelling function and speedometer input function are on adjacent pins of the instrument cluster plug so moisture intrusion might have been causing interference of of one with the other.

[34058]

Considering your use of a powerwasher, that might explain the problem with the speedo. The signal self-cancelling function and speedometer input function are on adjacent pins of the instrument cluster plug so moisture intrusion might have been causing interference of of one with the other.

I agree that power washing could get water into the electrics, but I am careful not to blast the vital bits like electrics, bearings and so on.  There was no water or corrosion on the instrument cluster pins, or in the connector from transmitter to wiring loom near the battery.

I have now got to dismantle the instrument cluster yet again to replace a dud bulb.  It has failed at the lower end of the speedo reading and  I don't want to get nicked for speeding.

David

[34058]

An update as promised.

I have now done about 150 miles and the speedo has been working perfectly all the time.  I'm going to leave it as it is because I can happily live without the self cancelling indicators.

David.

[Laitch]

  I'm going to leave it as it is because I can happily live without the self cancelling indicators.

Definitely!
I like them for high speed riding on the freeway though. 

[natalena]

It only played up on cold days with high relative humidity, but not raining,

That's about everyday, except the 3 non-consecutive days in August. ;)

Great to hear you're enjoying the ride.