Wednesday, 15 April 2020

QR50 - Generator Stator

Updated: first published March 2020

While we are in lockdown to slow the spread of Coronavirus, I have started to look at the QR50 electrics. It's pretty easy to solder up a new wiring harness in the office.

I'll write about the wiring harness in another post but first, before we start on that we need the stator casting repaired. You might recall I mentioned that it was toast and that I had bought a PA50 stator (complete) to replace it but that the PA50 stator does not fit...

Pictured here is the original stator, with all the wiring missing and the CDI sensor coil burnt out somehow. Fortunately the exciter coil is continuous, because the PA50 coil is bigger; the PA50 trigger coil however is identical to this one and will just swap out.

This is the back view. If you look closely at about 10 o'clock, you can see a crack in the casting. I did a little research on the Henkel website for a suitable cyanoacrylate that had low viscosity to wick into the crack and came up with Loctite 496, as a low viscosity adhesive specifically formulated for metals. Unfortunately the high temperature alternative, 4203, doesn't seem to be available anywhere so we will have to see how this goes.

Here's the crack, bound up with a bootlace...

And as if by magic, I now have a rebuilt stator. I've reused the existing exciter coil, which has just been gently cleaned. The trigger coil comes from the donor PA50 stator, and the wiring has been replaced:

Inboard view:

And here's the stator trial fitted in the offside crank case:


  1. Plz can you tell me where you get the complete PA50 stator
    i bought a stator from a PX50 think there's my problem my bike drives backwards

  2. You've got a problem with the ignition timing. Have a look at the piston position vs. the point at which the ignition is triggered - it should be some degrees or millimetres before top dead centre - I suspect your bike is very retarded, firing near top dead centre.