Can anyone please give me an idea of what and where the speed sensor should be on the original engine?

There's nothing obviously visible, either in the sprocket area, or a sensor coming out of the crankcase. There's a good deal of plumbing and venting tapped into the crankcase, so it's site may have been utilised. I do not have the original primary sprocket cover, so I don't know if the sensor would/should be found there.

What, therefore should I be seeing?

I need a speed signal from something, I'd like to recreate what should be there from Yamaha.

Thanks for any pointers.

Try lower crankcase, between the upper & lower mounting points on rear of engine. Should be sensor/hole pointing in direction of output shaft.

It's down near the out-put shaft and has a traingular plug on the end of the wires from it. Copied this from Rob Collinridges build site...


"19 - Speed Sensor
The speed sensor is fixed to the engine block but this is the only sensor I've found where the wiring colours don't match the diagram. They should be black/blue + white + blue/yellow but they are actually pink + orange/red + black/white. The wiring loom has a white triangular connector, 3 pins, 3 wires, blue + blue/black + white/yellow. Required by ECU from what I can see but other owners say it is only required if you use the R1 clocks."

Yep as above white triangular conector

Thanks guys, yep, just under the crankcase join line, to the right of the sprocket is the sensor. It doesn't look like a sensor, it's had it's wires cropped flush with the housing, but the sensor it certainly is.

I clearly need to get hold of one, and the plugs, then involve myself with lots of grief. I guess this is what I need:

yamaha yzf r1 speed sensor oem 04 05 06 RN12 | eBay

The car has an aftermarket dash/loom/everything so it's going to take some working out.

[Edited on 27/3/12 by motorcycle_mayhem]