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Intermittent Speedo & Tacho

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BlueLBike
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Solved Intermittent Speedo & Tacho

Post by BlueLBike on Mon 14 Nov 2016, 9:23 pm

Apologies if this has been asked before but my forum searching pulled up no results on the different combination of words to describe this that I could find so hoping someone can shed some light on this for me who may have had the same.

Bike: CBF500 2004 (Non ABS) 28k miles. Digital clocks.

So I'm having an intermittent issue with the Speedo and Tacho on my bike. This has only just started after it being sat outside in the cold and wet (albeit under an Oxford cover) for the past month. Before hand there had never been an issue with it whatsoever.

For the first mile or so of riding both the speedo and tacho will display readings as expected, however will then together die and lay at 0. Whilst riding they will occasionally spring back to life and display normal readings and then again die seemingly at random intervals. 

Odometer ticking up as normal, and temperature reading rises and falls as normal too. All other dash lights working too. 

Going over bumps in the road seems to not affect them working either which makes me think this isn't just a loose wire. 

Any help will be much appreciated.

So far I've tried checking fuses and checked wires coming from the instrument cluster to various sensors etc are secure which they are.
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liverpool_f_
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Solved Re: Intermittent Speedo & Tacho

Post by liverpool_f_ on Mon 14 Nov 2016, 9:36 pm

There are much fewer CBF500 owners on here than CB500 so I will do my best to answer. I think one of the differences between the 2 is that the cb has cable driven speedo and the CBF is electronic wheel speed sensor. Anyone else, feel free to correct me on that one.

If thats the case, then first step would be to make sure the sensor connector is tight, undamaged and free from corrosion. Give it a clean with contact cleaner and a few plugs and unplugs. After that I would turn to replacing the sensor. It is probably cheap. If that doesn't work, next thing to investigate would be the clocks but that is likely going to end up with replacement clocks as they tend to not be very serviceable.
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Taurus
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Solved Re: Intermittent Speedo & Tacho

Post by Taurus on Mon 14 Nov 2016, 10:14 pm

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Jameshambleton
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Solved Re: Intermittent Speedo & Tacho

Post by Jameshambleton on Mon 14 Nov 2016, 11:16 pm

This sounds like a very similar issue I have with my cb400sf, I've managed to get mine traced back to the wiring in the clocks rather than anything else but other than that I'm not too sure.

My clocks read fine until the bike has run for an amount of time and then the rev gauge bounces as it likes and my indicator flasher on the dash doesn't work over a set engine rpm, is it the same as yours or does yours just die regardless of revs?
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Solved Re: Intermittent Speedo & Tacho

Post by Baddi on Tue 15 Nov 2016, 12:11 am

Since it is a digital speedometer and it has been outside, I'm thinking that either something in the electronic has gone loose/broken due to temperaure fluctuations or something has gone wet. 

The first thing is not my first guess as I have a good feeling that Honda is a good quality, but shit happens and a bad solder could easily give problems. 

The wet thing comes a bit from my own experience on my earlier bike, which was not a Honda, but it had also been outside for a bit and some water had entered the connector to the speedometer and at first it short circuited the rev counter input to the speedometer input which meant that it were reading waaay wrong and then later it aparrently short circuited to ground because then it didn't work at all. After taking the connectors apart and drying and cleaning them, it has worked for a full season of 7000km on that bike. 

So it might just be as simple as some water having entered where it shouldn't be and are sometimes shorting signals to ground but still, you should not let it be for that reason as shorts are generally not good for electronics. Very Happy
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eternally_troubled
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Solved Re: Intermittent Speedo & Tacho

Post by eternally_troubled on Tue 15 Nov 2016, 9:07 am

The CBF has a speed sensor coming from the engine/gearbox, rather than a cable from the front wheel as we have our CB500s.

I wouldn't rule out a bad connection:  it could just be a connection that is corroded (you mentioned that it was outside) and only just making contact when it is cold but as soon as it heats up a bit it disconnects.

In fact, now I think about it, the fact they both go on/off at the same time (is that right?) makes me think it might be the power to the clocks that is not quite right...

Do you have a Haynes manual?  The wiring diagram and some understanding of how the clocks work might be helpful at this point :)  I've just managed to download one which I can give you a link to if you want (send me a PM or reply to this thread if you do).

Firstly disconnect the battery!

You should trace all the wires back from the clocks to wherever they go (this might involve taking the tank and other bits off) and take each connector apart and cleaning it.  Something like this will help:

http://www.maplin.co.uk/p/servisol-super-10-switch-contact-cleaner-200ml-jp17t

If you haven't got some switch cleaner then you can use WD-40/GT85 and a small screwdriver to scrape the corrosion off.

EDIT:

Just downloaded the Haynes manual and it suggests that the instrument connections go via the headlight shell - that should be even easier to get at.  Connections inside the headlight are common, they are normally squashed in.  Find the ones for the instruments and clean it up before doing anything else!


Sorry if you've done all this already, but it makes sense to start with the easy things first.
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BlueLBike
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Solved Re: Intermittent Speedo & Tacho

Post by BlueLBike on Tue 15 Nov 2016, 10:45 pm

All, loads of good points and gives me lots to look at over my rest days coming up (working shifts and currently working a week of nights means my daylight hours are limited and traded for sleep).

Taurus: I've had a read through that link and does seem to hint at a possible PCB issue from dodgy connections due to damp. Again, as stated by a few on here, this does all point to corrosion, dampness, or just generally something being a bit loose. 

James: Mine dies regardless of revs (tested last night through a full range of revs at the joy of my neighbours Razz) but all other lights work on the dash, including the indicators.

Baddi: Hoping to pull the instrument panel off in a few days and give it a once over with some emery cloth on any connectors and any soldering that looks like they may have gone awry i'll re-do. It is all pointing towards damp causing issues.

Eternally_troubled: They do both go off at the same time and kick back in at the same time yes. Thank you for the offer of the link but I already have one, I've learnt from working on cars without any prior knowledge just how useful they can be!! I'll give that a go soon, definitely seems a much easier task to remove the headlight then the clocks.


Thanks for all the info, will update here when I have a chance to work on my bike.
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Solved Re: Intermittent Speedo & Tacho

Post by eternally_troubled on Wed 16 Nov 2016, 7:32 am

Glad to see you've already got a Haynes - at least you can see how it *should* work, even if you can't fix it!

I'd have thought that if you were getting enough water in the clock-housing to cause significant corrosion then you would have noticed condensation, but anyway you will find out if you take it apart!


@BlueLBike wrote:

Thanks for all the info, will update here when I have a chance to work on my bike.

Work gets in the way of all the important things :)
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BlueLBike
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Solved Re: Intermittent Speedo & Tacho

Post by BlueLBike on Wed 21 Dec 2016, 3:18 am

So, after a brief spell abroad and a lot of overtime to pay for christmas (coupled with some amazing weather  Rolling Eyes) I have finally found a spare couple of hours to work on my CBF. Taking Eternally's advice I took off the headlight and found allot of the wires are indeed squashed into the shell. I pulled these out and traced the 2 sets of wire connectors for the instrument panel and found this:







Having tried (unsuccessfully) to clean these up with some sandpaper wrapped round a screwdriver I have gone out tonight and bought these (apparently they are used to file your nails into the 'right' shape scratch  ):



Being too late to go and work on it anymore tonight I have a couple of questions before I try to tackle this again soon.

1) How/what is the best way to clean the female end of the terminals?
2) Any chemicals I can use to clean the terminals a bit easier (thinking PlusGas or WD-40)?
3) If this all works, to save any more hassle it's been mentioned to me by a friend to coat the terminals (blades + connectors) with Vaseline??? Does this do anything other than make a horrific greasy mess that shorts out?

All the best and hope to be out on the road again before christmas  rendeer
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Jameshambleton
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Solved Re: Intermittent Speedo & Tacho

Post by Jameshambleton on Wed 21 Dec 2016, 8:52 am

1) WD-40 and plugging in and unplugging the connection
2) WD-40
3)  Vaseline is a waterproof thing so it'll stop the air and oxygen from reacting with the terminal so you won't get the corrosion buildup again
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eternally_troubled
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Solved Re: Intermittent Speedo & Tacho

Post by eternally_troubled on Thu 22 Dec 2016, 9:48 am

What James said just about covers it. You can use contact cleaner instead of WD-40, you can probably use break cleaner if you haven't got either of the above.

Use the emery boards you have purchased with care - first try scraping with a small flat screwdriver, plus unplug you battery first Smile

The vaseline *will* make a horrible greasy mess but it won't short out, in fact it might stop your connections working if you put too much in the wrong place (it is an insulator!).

Watch these two videos from youtube and you will get the idea about dielectric grease:

https://www.youtube.com/watch?v=yuKAmaIkA-U

https://www.youtube.com/watch?v=YgJRKlE7pYg

Essentially you'd be better using 'real' dielectric grease (it's usually a silicone grease) but whatever you are going to use, if you put it on those connectors only put a little bit on - remember it has to be pushed out of the way by the other half of the connector.

Also - thanks for taking the time to reply to this thread, it will be interesting to see if this fixes your problem (hope it does!).
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BlueLBike
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Solved Re: Intermittent Speedo & Tacho

Post by BlueLBike on Thu 22 Dec 2016, 4:51 pm

It's worked!!!!  cheers I can now avoid crawling around well below speed to avoid tickets and speed cameras! After a couple of hours spent gently scraping off the worst of the corrosion with the emery boards and then a generous soaking in a WD-40 & PlusGas mix and plugging and unplugging session on each of the connectors all is working fine again! I've invested in some dielectric grease to finish the job up and weather proof but for now it'll get me back on the road. Thanks all your help and suggestions and one hell of a welcome to the forum!
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eternally_troubled
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Solved Re: Intermittent Speedo & Tacho

Post by eternally_troubled on Fri 23 Dec 2016, 8:42 am

Glad to hear you've fixed it - those green slimey connectors did look a bit supicious Smile
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BlueLBike
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Solved Re: Intermittent Speedo & Tacho

Post by BlueLBike on Sat 24 Dec 2016, 5:27 am

Haha , yep, that and the cobweb in the middle top row of the black female connector is a testament to the job being overdue Shocked

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