Speedo Healer for the Tenere
 

The speedo on the Tenere is about 9% out. I was not too happy with this and when I changed the front sprocket to a 14 from 15 it got worse.
I like to know how fast I am going due to the masses of cameras in London.
I previously noted that the bike was doing 70 (GPS) when the speedo was reading 77 so some quick calcs:
70/77 = 90.9 x 14/15 = 84.8...... a 15.2% error.

I decided to fit a speedo healer at a cost of about �65 including postage. Small change when my last speeding fine was �550.

I decided to take pictures of the fitting to assist anyone else contemplating fitting one. My tank was half full when removed and did not spill any petrol at all.

First, all the grey plastics have to come off.
http://i310.photobucket.com/albums/k...y/sized_S1.jpg


Beware the small spacers, they fall out and have a mind of their own.
http://i310.photobucket.com/albums/k...y/sized_S2.jpg


Next is the rear tank bracket, again, watch the spacers, they fall out when the tank is lifted.
http://i310.photobucket.com/albums/k...y/sized_S3.jpg


Remove the front long silver bolts from under either side of the tank and also the two black plastic brackets in front of those (3x 8mm bolts each). At the same time, slip off the tube on the left side behind the long bolt. Mine did not spill any fuel. Note the rusty thread on the bracket. It was the same both sides and made romoval of one of the side panels a problem, had I left it much longer I am sure it would have seized solid and broken away from the bracket - rust inhibitor used for reasembly
http://i310.photobucket.com/albums/k...y/sized_S4.jpg


This is the hard bit. wiggle the tank up whilst keeping it roughly level and get someone to chock the rear up with something so you can get to the fuel line and electrics. The green and white plugs are simple enough to remove with the usual press catch on one side. http://i310.photobucket.com/albums/k...y/sized_S5.jpg


Now remove this clip from the fuel line and it will allow you to then squeeze the blue tabs on the fuel line and pull it off. http://i310.photobucket.com/albums/k...y/sized_S6.jpg


Now lift the tank off. This is what it looks like underneath. http://i310.photobucket.com/albums/k...y/sized_S7.jpg


Now you can access the speedo sensor cable. Its the 3 pin white one above the tappet cover, centre screen. Pull this plug apart. Care is needed when pressing the catch as it is a bit like a fish hook and the plug needs to be pushed together slightly before pressing the catch and then pulling the whole thing apart. (hope this makes sense). http://i310.photobucket.com/albums/k...y/sized_S8.jpg


Once apart it is a simple matter of inserting the male and female of the Speedo Healer lead into the now exposed female and male of the existing plug.
All that remains is to plug the new lead into the Speedo Healer, plug in the supplied extra 2 pin lead and switch (not absolutely required unless you want to know you max speed recorded) tidy it up and find a place under the seat for the Speedo Healer bearing in mind that the buttons need to be accessible (not easy if you have other bits attached under the seat) and then calibrate it to suit your set up. http://i310.photobucket.com/albums/k...y/sized_S9.jpg


This is where mine ended up. I may move it yet. I have a relay, an Autocom, an MP3 player and battery pack squeeze in too, so space is tight. This is probably my main criticism of the Tenere when you consider its intended use. http://i310.photobucket.com/albums/k.../sized_S10.jpg


The settings are (for my bike anyway) -9.1% for the speedo only and -15.2% with the smaller 14T front sprocket. Follow the instructions sullplied to program it.

I will calibrate the unit and test it against TomTom tomorrow. I'll let you know if it is any good.

OGR

Thanks Ray I will add this to the mod section.:thumbsup[1]:

I think I might have got it?
 

That's a comprehensive report, thanks Ray (I had my tank up the other day too, it's a bit of a fiddle as you say - I can see the price to check/adjust the valves being pretty high labour wise...)

As a thought - Presumably the speedo reads off the gearbox output shaft? - hence the smaller front sprocket spinning faster shows a higher top speed right?

Now correct me if I'm wrong (I'm no mathematician) but you kept the 15T front and you put a larger rear sprocket on instead (say 47 teeth), the rear wheel is now effectively turning slower for the same engine revolutions? - would than not correct the speedo over-reading?

If so, perhaps this is the problem - that the bike actually ought to be running slightly lower gearing (that is using a larger rear sprocket), but they put on a 45 tooth in an effort to keep the revs down at speed and improving MPG?

I'm going to try it next time I fit a new chain and sprockets...

xxx

Placing a 47 on instead of a 45 would do the same thing as going from 15 to 14 on the front (well about 65% of it anyway). The pickup is indeed in thre gearbox and the only way to make the speedo read correctly would be to put something like a 42 on the rear or a 16 on the front. Both these would likely make the bike struggle in top gear against a strong wind or slight incline and make off road a nighmare.

The calculation is a simple division sum. e.g.
Standard ............45T/15T = 3.00
Mine ..................45T/14T = 3.21
Your proposal ... 47T/15T = 3.13

I have now calibrated the speedo and I have programmed in an 18.5% (Yes 18.5%) correction to get the speedo to agree with TomTom. This is all very dandy and I now know exactly how fast I am going but the downside is that the odometer is now out by about 7%. After 100 real miles my odo thinks I've only done 93.

It appears that in the stock setup the gearing is correct for the odo but way out for the speedo - possibly in a vain attempt to slow us down.

Please educate me. Why would a GPS speedo reading be necessarily more correct than an OEM speedo reading? The former is being read off from a satellite which is thousands of miles above where the bike is. From what I've read so far, it seems to me that there is a general assumption the GPS reading is more accurate than the OEM's, why?

If GPS was inaccurate it would be no good for telling you where you are :)

The satalites may be a long way a way but by triangulalting the distance from up to 6-7 satalites at one time a gps unit can give you a pretty good indication of your actual land speed which is going to be quite accurate.

An oem speedo may not be necessarily inaccurate but are usually made to show a higher speed than is actually done in an effort to keep actual speeds within legal limits (as most people seem to speed by just a few mph)

I understand what you say but as DEIACCORD states they are as about as accurate as you are going to get and I have tried it over long distances in order to get as accurate reading as possible. The GPS and the speedo very nearly agree with each other to +/- 1mph at 70mph.

Over a short distance it would be innacurate as sometimes the fix can be 10m out and if the next fix it gets a few seconds later is 10m away it could record you as doing some ridiculous speed even when standing still. the better ones average the speed out over a time for accuracy.

Thats a very good point!

Ah yes, but,,


and,

The statalites are controlled by the US military, and can be made very innacurate at the click of a mouse. I'm not sure about other countries ability but in the UK we also have WASS (Wide Area Augmentation System - bet you didn't know that one, eh ??) which is a land based system that can increase the accuracy to within a few feet. This is a system favoured by maritime GPS, but devices like the Zumo also support it. The downside of WASS (being land based) is you can often loose the signal if you are 'out of sight'

So, the GPS system bases your speed on time between two points, ergo it is more accurate the faster you go. However, I belive that the calcualtion is based on 2 dimensional movement (even though your GPS operates in a 3 dimensional plane), so descending a steep hill will give you a slower reported speed that actual speed (going up hill, your reported speed will be slower than you actual speed) If you want accuracy, then a Road Book is the way to go, but then over rough terrain when the wheel is spinning (off the ground), or your wheel circumference has changed (like you've used some tread) you again loose accuracy.

The problem is that the only real way to check your speed is to measure the time between points, but this is only average. To get real accuracy, you'd need something like a laser speed detector (even so this is still only an average over a very short distance). So here we are agaim, the Police have access to the right gear, but we don't - and we're the ones who'll get shafted as a result!

All of this is academic realy, the more accurate you become, the closer you have to watch your speed.......... :signthankspin:

Waas
 

Actually we don't.... we have EGNOS or the European Geostationary Navigation Overlay Service

Nah, nah, de, nah, nah

:boxing:


:rotf[1]: