The output shaft oil seal on my 907ie appears to be leaking. Does anyone know the size so that I can have one to hand before starting work to change it?

I don't know the size but Stein Dinse is always a good source for such info. It's part 8, right?
https://www.stein-dinse.biz/eliste/elis ... 544g&lg=de
That would be
https://www.stein-dinse.biz/images/prod ... 832552.jpg

Corteco 25-52-7 BASL DRW (or is that 62?!)

BA = rubber shrouded
SL = second lip (against dust & dirt)
DRW = double sense of rotation

The last seems logical. I'm stunned to learn that there's actually a RD-RH and RS-LH spec which are for right or left hand rotation.

Yes, I'd spotted that image and assuming that it's the actual seal and not just a generic image then it will be 25mm ID x 52mm OD x 7mm Width. I guess I'll just have to pull the sprocket off and have a look. I was thinking of replacing it with a Viton R23 (double lip) seal.

Hi Derek
Can you let us know any tricks/tips if you get there before me. I have just ordered one.
Cheers Tom.

Sorry Tom, I haven't done anything about it yet and will probably leave it until the winter. I don't foresee any problems though - remove the sprocket, screw a self tapping screw into the old seal to provide something to grip on then attach a pair of pliers or similar grip and pull the seal out. I'd apply pvc tape over the fluted part of the shaft to protect the lip when fitting the new seal and oil the seal before fitting. Gently tap it down square with a suitable drift (tube, socket or whatever). Refit the sprocket. Job done.

Just done mine Derek and it was as simple as you said.
I ordered the seal, my one error was to order a single lip seal. However it is so easy to change that Im not too worried if it does nt last.
Cheers Tom.