no power to dash! help needed please!!

Hi i dusted of my 2006 m800 for a spin last week with the intention to mot it all went well until i tested the horn as a truck cut me up damn thing had given up the ghost! as it is an aftermarket car air horn i though it was just dry so held the button on while riding down the A9 (this usually gets it going again after a long stand over winter) horn still didn't work then i noticed i had gone from a steady 100 kmh (german import bike) to nothing, then as riding along i looked closer and realised there was no milometer either so headed straight home, got home stopped the bike (was worried about it not starting again!) tried to restart it, still no power to milometer no test on speedo (needle usually goes all way to end and back again) but it still started and everything else works (lights, turn signal and real light still no horn though!) I have just started stripping down the bike today after a casual look at the fuses under the left hand cove can't see any problems although I might just pull every fuse to double check. 

Has anyone else had an issue with there speedo given up the ghost or am i just special!! lol I do ride it hard and am kinda thinking i might have a dodgy connector block but just would like some other advice before i get to involved with the loom! (I hate electrical systems!!)

As we speak i am going to double check the fuses

Any help would be grateful also do i need a speedo for the mot as i do have an electronic speedo on the handle bar for mph?

Many thanks

Kev

Hi Kev

I take it they were both working before you laid the bike up & have both packed up at the same time ?  If that was the case, I'd be tempted to disconnect the horn & see if this has any effect.  Was the horn wired through the existing horn switch or has it had a relay fitted - the air horns draw a lot of juice & can fry the switch if not routed through a relay.  Not knowing much about the VZ, I'd guess it has an electronic speedo with a separate base unit with the tell-tales.  I'd pull the block off & run a continuity test to make sure I was getting feed to the specific pin on the block - at least that'd narrow it down to the speedo head or wiring.

Far as the MOT goes - just had a look at the MOT regs & surprisingly, whilst you need one for C & U regs, i cannot see that not having a speedo as a reason to fail.  I'd be asking the MOT tester in advance & if he says it needs one, ask him what the reason for failure would be if you didn't have one.  However, it is a legal requirement for the vehicle to be fitted with either an digital or analogue means of indicating the speed.

Hi kev
I had exactly the same issues.... the speedo packed up randomly, in that it was doing what you say... One minute 130,mph, next minute 5mph. The very clever mr intruder remarked that the horn and speedo are on the same circuit... And as I had fitted an aftermarket horn, figured that might be the issue.

So reconnected the original horn, and all was well.

But only temporarily..... Eventually the speedo started misbehaving again. I cleaned and vaselined the horn terminals.... Nothing.

This was now beyond me. So I faced a tough choice...buy a new speedo (about £399 from mr Suzuki), buy a used one (about £100, and might still go wrong), or ask garage to diagnose.

Suzuki agent wanted silly money.... So in the end I went with an under the arches place near work, who spent hour after hour on it, and couldn't find the fault. Then as they were reassembling, one of their mechanics suggested re-soldering all the joints on the back of the speedo circuit board....result!

I don't do big miles, but it's done 2000 miles since then and not missed a beat.

Of course yours could be some totally different fault, but thought this might help. Let us know how you get on

Thanks for the reply guys, spent an hour on it yesterday and found the the problem, surprising what a full belly and a decent nights kip will do!  it was a fuse the other week i only pull out the ones i thought could be faulty but after pulling them all out the one i left till last said signal which i assumed to be turn signal! put a new fuse in and hey the dash came back to life briefly before popping again, after your comments dave i pulled the horn off the loom (yes you were correct the previous guy had wired it straight into the loom so i will need to correct that after the mot) changed the fuse again and all good so i pulled the horn apart and found the contacts to the motor were corroded so cleaned them up and cleaned up the horn switch contacts in the switch gear and all is well! 


Now i can book in for the mot thanks again for the advice dave and mal i am glad it turned out to be a simple fix i was dreading the re-soldering work on the circuit board! or digging deeper into the loom thanks again guys 

Surprising how much a small bit of corrosion can gum up the works - & how a nights sleep can help.  Glad to be of help - your membership fees have paid paid for themselves already - what do you mean you're not paying membership fees !!!  Good luck with the MOT

A speedo must be fitted for an MoT but it does not get checked to see if it's working just to get a reading to put onto the certificate unless your man has a rolling road specifically designed for a bike as a car one will not suffice to do the job properly, this came from my MoT man direct!

peardrop3 wrote:

A speedo must be fitted for an MoT but it does not get checked to see if it's working just to get a reading to put onto the certificate unless your man has a rolling road specifically designed for a bike as a car one will not suffice to do the job properly, this came from my MoT man direct!

That's what I thought Pete, but I can't find a "Reason For Rejection" code on the MOT regs - my understanding is that if there is no specific "method of inspection" or "reason for rejection", then you can't be tested on it.

I think it needs to have one but they can not test it, so in theory I suppose it does not have to work, good luck with the speeding fines though :) I read some where that someone fitted a push bike computer to his motorbike and one of those horns you squeeze to get it through its MOT, I do not think it had any lights or indicators though.

My mate Keith who has over 40 vintage & veteran bikes uses a push bike speedo most of the time unless he has reason to get a bike registered when he'll fit a real speedo but it has no works in it & the drive cable is empty also. All his bikes are pre 1960 anyway so no longer need an MoT anyway.