hi there
i have an acewell speedo with an fireblade engine been trying to program speedo with no joy

i have 15" wheels

the magnet is on the propshaft as been suggested before hand

the problem i have got the speedo reads fine up to 20-25 mph then after that it is very eratic eratic

can any one help?????

More magnets?

i had the same problem, its because the sensor is the wrong way round. if you look on the acewell web site in the faq section and it will tell you.

As has already been said sensor placement is critical - it shows in the instructions to align the sensor so the magnet passes a marked line on the sender

ok cheers guys
will have a look at the sensor later as it is fitted so the magnet goes through both parts of the sensor

I had a similar issue with a Vapor in the propshaft...fine till about 28 MPH then rubbish numbers.

The reason was that the propshaft magnet was revolving too fast and the sensor never not saw it (if that makes sense). Moved the magent and sensor to the rear wheel and everything worked fine.

The Acewell is a great unit, the magnet I got with mine is built into a small bolt, made installing it a piece of piss, drill and tap a hole in the outer joint and mount unit on the rear upright. no calculations of diff ratio required. don't forget the centre bearing on the prop is rubber mounted so at the speed a blade spins at you will get some deflection
Rescued attachment speedo pickup mount.jpg

Can't you use the original honda sender unit to the acewell?
I know, on the Blackbird at least, that the sender pulses between 0-5v which is what the acewell unit wants to see. Just requires a bit more maths to factor in the gearbox final drive ratio and the diff ratio.
Unless the fireblade uses a mechanical speedo - not seen one up close.