Speed sensor - inexpensive alternative to OE unit

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edvard · #1 Post by **edvard** » Sat May 03, 2014 2:12 pm

I need a new speed sensor and came across this on an RSV forum:

http://apriliarsv.com/guides/16285-inex ... r-fix.html

Has anyone done this, or something similar, on a Falco?

Looks like you can pick up these sensors on ebay for £3.70 incl shipping - somewhat cheaper than the Aprilia sensor, which is currently on ebay at nearly £70.

blinkey501 · #2 Post by **blinkey501** » Sat May 03, 2014 5:20 pm

First of all welcome to the forum.
I have never heard of anybody doing what you have suggested with the part you have shown on RSV zone.
But at that price I would give it a go.
Someone posted on another forum that they had used a ducati part and cut the plug off the ducati sensor.
They then soldered the aprilia plug and some of the leads to the cables of the ducati part and heat shrinked the two together.
The ducati part was a fraction of the cost of the aprilia part.
If you decide to go with the part on ebay let us know how you get on.

edvard · #3 Post by **edvard** » Mon May 05, 2014 6:55 pm

Cheers for the welcome.

I agree. As the sensors are so cheap it's worth trying, especially as the original poster clearly knows his stuff and the follow-up postings on the RSV forum are so positive. I'm assuming the RSV's pretty much identical to the Falco either side of the speed sensor, ie where the sensor counts the bolts on the rear wheel, and how the resulting signal gets converted to speed by electronics in the dash.

I'll let you know how I get on.

blinkey501 · #4 Post by **blinkey501** » Mon May 05, 2014 6:58 pm

edvard wrote:Cheers for the welcome.

I agree. As the sensors are so cheap it's worth trying, especially as the original poster clearly knows his stuff and the follow-up postings on the RSV forum are so positive. I'm assuming the RSV's pretty much identical to the Falco either side of the speed sensor, ie where the sensor counts the bolts on the rear wheel, and how the resulting signal gets converted to speed by electronics in the dash.

I'll let you know how I get on.

The falco and mille are almost identical in every way apart from the obvious. Frame and panels etc and the swingarm
The mille uses the same speed sensor.

wayno · #5 Post by **wayno** » Tue May 06, 2014 8:04 am

Hi Edvard, I made one of these, but bought an original part as the jap version of the sensor took 6 weeks to arrive. I have never tried it for speed (it registers a few mph spinning the wheel by hand), unfortunately my bike is uninsured at the minute so I have no way of trying it (long sad story).

As you're only in Oxfordshire, you're more than welcome to try mine for free (I'd want the housing bracket back at some point though).

wayno · #6 Post by **wayno** » Wed May 07, 2014 8:56 am

Here's what I came up with if you want to try it

edvard · #7 Post by **edvard** » Wed May 07, 2014 6:54 pm

That's a very nice bracket you've made there! I sort of had in mind that I'd try re-using the standard sensor housing - drilled out. If my fabrication skills were better, I'd certainly do something like you've done.

Many thanks for the offer... I've ordered a sensor from Hong Kong and they say it's up to two weeks for delivery, so I'll see what I can come up with. If the standard housing doesn't work and I don't have any other bright ideas, I'll give you a shout.

In fact - thinking about it for a couple of seconds - I'm sure my local engineering shop could produce a copy of yours easily, if I knock up a dimensioned drawing. Thanks for the inspiration!

wayno · #8 Post by **wayno** » Thu May 08, 2014 7:00 am

No worries, just to give you a heads up, I'm pretty sure the thread on the outside of these sensors is M12x1.0

edvard · #9 Post by **edvard** » Thu May 08, 2014 9:52 am

Aha, so you tapped the housing too - I didn't pick up on that from your photo. I assumed you fixed the sensor's position with a nut on either end. A threaded housing obviously makes fine tuning a bit easier, which is probably important as I gather the sensor head may need to be as close as 0.5mm from the bolt heads on the wheel.

wayno · #10 Post by **wayno** » Thu May 08, 2014 9:58 am

The position is locked using the nut and washer that is in the picture, to install it simple wind the sensor right out, put the housing in place of the normal sensor, then wind the sensor in until it is about 1mm from the nut, just make sure that you slowly turn it and that none of the nuts stick out further than the others or you'll smash up the new sensor.

By the way, when I tried to solder my existing wiring onto this new wiring I found that the wires coming from the original sensor were black and wouldn't take solder so it can be quite tricky.

edvard · #11 Post by **edvard** » Tue May 13, 2014 7:35 pm

The new sensor arrived from Hong Kong and I fitted it using the original sensor as a mount by drilling it out. Took the bike out for a test ride and found it works fine... up to about 50mph, at which point it says that's too much for me and returns the display to 0mph. Reduce speed below 50 and it rejoins the party.

I'll experiment with adjusting the gap between the sensor and bolts and see if I can get some improvement.

For those that are interested, the sensor I bought (for £3.70 incl shipping) was an Autonics PR12-2DN and the digits in the code, like spark plugs, mean things. In this case P=inductive proximity sensor; R=cylindrical type; 12=head diameter; 2=standard detection distance; and DN=NPN Normal open (DC 3-wire output). That all makes sense to me, except the NPN bit. However, according to the original poster on the RSV forum, this sensor is good for recording speeds up to 170mph, so I'm hopeful I can get it working at all speeds.

wayno · #12 Post by **wayno** » Tue May 13, 2014 7:43 pm

Nice work, fingers crossed you can get it working, if nothing else it'll be good to keep as an emergency spare for up to 50mph