Is this a Speedohealer?

[Fallout]

Been having issues with my speedo on my GSXR750 K1 since changing the sprockets and chain (to DID standard spec replacements). Speedo could read for a couple of minutes no problem, then would drop out and read 0. Changing gears, giving it beans, starting, stopping .. no obvious cause. Last ride it red 74 while doing 20mph round a roundabout, then I hit 245 mph a few seconds later! DAMN FAST!

Anyway, assumed it was a loose/corroded connection since it worked sometime, but having taken the fairing off tonight I spotted this box between the speed sensor (reading off the front sprocket type), and the instruments. I removed it, plugged everything back and and span the rear wheel, and speedo is still reading a few MPH, so it's working.

So is this one of those speedohealer type things? If so, anyone know which one? I've googled all the versions of the speedohealer and none look like this. I'll leave it off and take the bike out tomorrow for a proper speedo test. Hopefully just taking it off will fix it, but don't want to bin it. Could be useful if I can identify what it is. Or am I being a complete fool and it's actually something really important?!



Edit: Btw, there is no display or LEDs anywhere on the box.

Any per marking on the box? Any Writing at all?

[Fallout]

Nope. 100% blemish free. Only features not clear in the photo are a few square plastic "brackets" which take a zip tie for connecting it on.

[tigersaw]

so it went in series with a cable, and you have now just removed it and joined the cable back up, i.e. removed it like a link in a chain?
If your speedo now works it could well be a pulse divider, but what will the accuracy be like, assuming it was there for a reason

[Bibio]

you could try looking here http://www.ronayers.com/Fiche/TypeID.../2/Make/Suzuki see if its on the parts list.

might be a voltage regulator. when i first seen it i thought TRE but then they are connected to the gear selector.

[Fallout]

Yep, exactly that. It was in series. What makes me believe it was an aftermarket addition was a) speedo still appears to work, and b) both plugs on the device are white, but the sensor connector is black and the connector to the instruments is black. With it removed I have to black connectors again, which looks right. Defo aftermarket.

What would a pulse divider do? I'm guessing that's the function of a speedo heeler? Take the incoming pulse frequency and reduce or increase.

[tigersaw]

Yes, it would modify the pulse train to change the speedo readout.
Most obvious would be to make a KM speedo appear to read in MPH

[Fallout]

@Bib - Thanks for the link mate. Missed your post before. That's a cool site. Didn't know it existed! Unfortunately after about 15 minutes of searching I couldn't find the speed sensor on the wiring diagrams and there wasn't a speed sensor 'nut' (the thing the sensor reads held on by the front sprocket nut) on their transmission diagram, so I don't think they're necessarily complete.

@Tig - You could be right mate. I've heard gsxr speedos can be programmed easily to switch between kph and mph from the instrument panel itself, but that may be just for newer bikes. If I get crazy high readouts tomorrow then you'll be right. Will report back.

[Fallout]

The pluggy thing was indeed KPH to MPH converter. Never spent so much time doing triple figures! Fingers crossed someone was just a pleb and didn't realise it could be converted on the dash with a view button presses, but not holding out much hope.

[tigersaw]

If you cant alter your speedo then maybe the gizmo will work after a clean up - least you know the problem now