Speedo issues, GSXR front end, hall effect sensor?

[DavieSV]

Hi all.

I've fitted a Hall effect sensor to pick up off 8 magnets on the front disc.
1st ride this morning,
After filling up with £22 worth of fuel
I did an average of 4mph all the way to work.

Questions:
Do the magnets have to have a specific pole towards the sensor?
(I have all the magnets with the poles in the same dirrection)
Is this just the cause of the sensor being too far away?
(I have about a 4mm gap at the moment)
Do the center of the magnets have to be in the exact center of the sensor?

[DarrenSV650S]

They all have to be attracted to the sensor.

4mm is probably too close. It happened to me and moving the sensor away by a washer's thickness cured it

[TamSV]

As Darren says, too close is just as bad as too far away. Mine is a few mil further away than yours.

The sensor I've used had to have the magnets passing at either end and wouldn't work if they passed the centre. This was the sensor that came with the Acewell clocks so it might depend on the particular make of sensor I guess.

Originally Posted by DavieSV

Hi all.

I've fitted a Hall effect sensor to pick up off 8 magnets on the front disc.
1st ride this morning,
After filling up with £22 worth of fuel
I did an average of 4mph all the way to work.

Questions:
Do the magnets have to have a specific pole towards the sensor?
(I have all the magnets with the poles in the same dirrection)
Is this just the cause of the sensor being too far away?
(I have about a 4mm gap at the moment)
Do the center of the magnets have to be in the exact center of the sensor?

The magnets all have to be the same and the right way round, or did on mine anyway. As for the distance I put mine about 4 mm away and didn't have any problems. Sounds like you need to fiddle with it a little

Bunks

[DavieSV]

Thanks for the help

Turns out the magnets were the wrong way around

I put them the other way and bingo, I kept the sensor the same distance and every thing seems fine.

Word of warning tho'
Dont bake the epoxy resin to harden it if you use glue for the magnets,
The heat weakens the strength of the magnets
I didn't realise this untill I was informed by someone in the know.
Evey day's a lesson.
For my set up, it didn't matter the sensor still works fine