How do you ream a bushing?

[Ozmadman]

All looks good!! and the position of the oil seal is one picture I haven't got (slapped hands!) I can't fully remember but I seem to think that seal does go further into the casing but even when correct it only just seats on the spacer. Maybe clanger knows as he has his box in bits still I think. Look at picture (24) in the attached link, its vague but the casing where the oil seal goes is deeper than the thickness of the seal and there is also a faint line around that hole so maybe this is where the outer edge of the seal was? Also did you fit it as in picture and comment (25)? hope this helps

[clanger9]

That looks fine to me. Which way round have you got the spacer? I'm assuming it goes in with the wider diameter towards the bearing.

[Steve S]

Thanks guys, I have the spacer in the correct way round but it moves in and out by several mm leading me to think the oil seal should be pressed further in.

When I loosely bolt the sprocket on it binds on the oil seal and won't turn, but maybe that was what the strange brass ring (shown in an old photo I took on disassembly) does, ie lengthen the spacer by a small amount?

This old photo is not very clear but it does look like the edge of the oil seal is slightly sunken into the case, what do you think?

Clanger do you have your box apart still or maybe Ozmadman can see on his spare box?



Steve S.

[clanger9]

My 'box is still on the bike! It's not Winter any more and I don't want to take the bike off the road unless I really have to.
The photos I posted are from the two "spare" gearboxes I have here. One is knackered and one is good (off a G2, not a CSR) and I've been collecting all the bits I need to overhaul it (and fix the chronic oil leak).

Looking at the parts I have, it seems that the outer edge of the spacer is supposed to be flush with the outer edge of the seal. Then when you tighten up the sprocket, it won't bind on the seal.

PS: I really wouldn't use that brass "spacer". The sprocket nut needs to be done up effing tight and that thing looks far too weak...

PPS: I'm pretty certain your seal is back-to-front in that photo. That's why it's binding.

[Steve S]

Thanks Clanger, the last photo posted is the box as I found it. I put the seal in with the lips inwards and the metal surround outwards, is this correct?

Steve S.

[clanger9]

Yes, flat metal bit outwards - the exploded engine drawing shows this (and the spacer) pretty clearly. The seal is round the wrong way in your photo.

If the spacer is flush with the flat metal surface of the seal, then the sprocket shouldn't bind (?)

[clanger9]

PS: on closer inspection, the seal is only about 1/2 the thickness of the casing. So the seal outer surface shouldn't be flush with the outer casing like it appears in your photos. I think it's supposed to be pushed further in to the casing until it butts up against the outer bearing race.

Does that make sense?

[Steve S]

Yes it does make sense as when I tapped the seal in I was aware there was no step to prevent it going further than flush. It will then sit fully on the spacer rather than right on the edge as at present.

[clanger9]

Further confirmation: there's a fairly clear witness mark on both of my gearbox cases that shows that the seal was pushed all the way in to the casing and up against the bearing. So that's probably where it needs to be.

IMG_1103.jpg

[Ozmadman]

And that confirms what seems to be shown in that gearbox rebuild pdf doc I posted earlier. Put the spacer in the seal and then tap fully home until it touches the outer race of the bearing then put the output gear through the bearing and spacer. Sometimes the spacer is a tight fit as it goes over the output gear but this will sort itself out when you tighten that large nut. My spare box is complete with the sprocket on it so I cant see the seal but if you are still tearing your hair out after all of this and want confirmation I will get the sprocket off and have a look