After accidentally overfilling the gearbox oil i appear to have a leak in the front sprocket/gear selector area. I have got replacement seals, how easy are they to fit?

very easy....
1 - remove sprocket,
2 - Take small screwdriver and knock it at right angles to the seal,
3 - Simply flick out.
4 - To replace, wrap some tape arounf the shaft and slide the seal into the housing.
5 - Using a suitable press (large socket) drive the seal untill it is seated, you may even be able to push it in . **Dont hit too hard as you may damage the seal!**
Jon

Ideal thanks for that, is the gear selector seal as simple?

yep exactly the same. just remember the tape or you will trash your new seal. Jon

what do you mean by tape?

The splines on the shafts act like little knives on the lips of the seals. Just cover the splines with a layer of insulation tape. Then lightly oil the tape with clean oil and the new seals will pop straight over the shaft with no damage.

I just replaced the sprocket seal even though it appeared fine, there were no sharp bits on this. When i tapped it back in it went back further than the old seal, its now 4-5mm down from the edge of the casing, is this too far?

tomh wrote: its now 4-5mm down from the edge of the casing, is this too far?

Try it and see, as I can't imagine it being easy to get out again.

In the case of a crank seal, pushing it in too far is bad as it blocks the oil feed to the bearing (IIRC). I don't think you will get anything worse than a not-sealing-seal in the case of the output shaft seal.

it wasnt easy to get out in the first place, it was in solid and i had to butcher a bearing puller to remove it with. I have started the bike up without the front sprocket on and it hasnt leaked yet

Just re read this thread, i replaced the big rubber seal that goes aound the sprocket housing, between this and the shaft there is a round metal bush that has a thin rubber seal in the back of it, is this another seal that i should have repalced?