Universal speedo/tach install?

[GOPSTER]

Hi

I have just bought a cheap universal speedo and tacho off Ebay for a BMW r80 project.
http://www.ebay.com/itm/Universal-LCD-Digital-Speedometer-Odometer-Motorcycle-MotorBike-F1-2-4-Cylinders/371181829584?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%2 6asc%3D20131003132420%26meid%3D3a52cb49ea514d57960 ecc9f7c47aff3%26pid%3D100005%26prg%3D2013100313242 0%26rk%3D3%26rkt%3D6%26mehot%3Dpp%26sd%3D271612466 392&rt=nc

I have wired it up and everything lights up fine except it is not measuring the speed correctly. It has a magnet and receiver that i have mounted, the magnet is the wheel nuts and receiver on a bracket off the bottom of the forks, they pass within 5mm of each other. I have set up the speedo for the circumferene of the tire (192cm) the instructions aren't great. The speed is showing max 5kmph.

Does anyone have any experience with these? Have I worked out the circumference wrong or is the magnet too close the centre of the wheel?

Any help would be appreciated.

[mossy1200]

Is only counting number times passing as signal so distance shouldn't mater.
My Koko unit works ok with same system.

Maybe program is wrong or have you set it up as having 6 magnets etc.

[bogan]

Make sure the magnets have the correct pole pointing towards the sensor, and make sure the unit is set for the correct number of them.

If those are both done correct, fuck with the circumference a bit, and just make sure it reads stable, may be it is set for radius, inches or some other thing...

[mossy1200]

Hi


. I have set up the speedo for the circumferene of the tire (192cm) the instructions aren't great. The speed is showing max 5kmph.

Does anyone have any experience with these? Have I worked out the circumference wrong or is the magnet too close the centre of the wheel?

Any help would be appreciated.


It looks like it may need be programed as 810 with 2 magnets or 405 with 4 magnets.
The instructions on the ebay listing are crap if that what you have to work with.

050m may be 0.5 meters saying read frequency needs be between 500mm and 999mm so your 1910mm needs be halved and 2 magnets required because one is outside the scale max or 1910 quartered and 4 magnets used.

[nodrog]

make sure your wheels nuts are actually magnetic.

low iron bolts/nuts wont work.

[mossy1200]

I assume your wheel and disc set is like mine.
I drilled the allen key bolt head like you would to lock wire it. I then filled the hex with no more nails and set the magnet inside the head N facing receiver but the magnet not touching any metal only the no more nails. My magnets are smaller than the hex hole in the bolt.
If you need some magnets like mine let me know. I have some spare.

[BMWST?]

to work out the actual circumference put a mark on the tyre where it contacs the ground and put a mark on the ground there too Push the bike for 1 revolution of the wheel put another mark on the ground there.Park bike.Measure actual distance between the marks on the ground.The only error you will have now is if the tyre grows slightly at speed or if you let the pressure go down.You will have an more acurate speedo than most.Re measure when you get a different tyre.A helper is best

[Warr]

Hi

I have just bought a cheap universal speedo and tacho off Ebay for a BMW r80 project......................

Any help would be appreciated.

Give us a call.. says you are in Hamilton, I can come and have a look for you ..

I'll PM you my number :)

[GOPSTER]

Thanks everyone. Will try remounting the magnet and measuring in actual circumference.

Warr I will give you a ring during the week.

[GOPSTER]

Have finally finished the rest of the bike and been able to have a good play with the speedo. The tip about marking the wheel a measuring 1 rotation was great, the actual circumference is 1805mm. The Chinglish instructions are actually correct on how to hook it up, except the maximum wheel circumference possible is 999mm. So I have added another magnet (round the right way) and halved the circumference (902mm) and all is working well.

Thanks for all the input and Warr for the offer of assistance

[Warr]

Have finally finished......., and all is working well.

Thanks for all the input and Warr for the offer of assistance
Sounds all good, pleased the scientific method came through !
Can you post up a PIC or 2 to show us the final result ☺