Breather rotor

cbranni · Post by **cbranni** » Sun Jun 10, 2012 9:00 pm

I an trying to help out a fellow member with a lightweight breather rotor, can any lightweight owner who has a rotor lying around check what the length is please. As far as I can find out this rotor is common to all years and models of lightweight, so before I cut metal I would like confirmation of the length, there is a prize for the first correct answer........... a three month old battery in need of some restoration

Cheers Colin

itma · Post by **itma** » Sun Jun 10, 2012 9:25 pm

not all the same
I had no end of grief with one some years ago
regret pics have been deleted.
not quite your problem but indicative of the pitfalls of G2's maintained by previous half wits .

http://www.ajs-matchless.com/topic.asp? ... F+Model+14

Janet · Post by **Janet** » Sun Jun 10, 2012 10:33 pm

Please will someone tell me what a lightweight breather rotor is and where I can find one. This would appear to be one of the few parts I haven't managed to break yet so I'd be interested to know what to look for when it happens.

cbranni · Post by **cbranni** » Sun Jun 10, 2012 10:48 pm

Hi Janet, the rotor fits on the drive side axle between the two bearings and revolves with the axle, the stator also fits tween bearings but doesn't revolve with the axle, its fixed to the crankcase either by a horrid hollow bolt from the gearbox side of the crankcase in line with rear chain (on early models) or by an internal bolt in crankcase (later type) both rotor and stator have holes in and when they line up every stroke/revolution any pressure in the crankcase is released through the hole towards the gearbox. Hope that makes sense

Colin

Janet · Post by **Janet** » Sun Jun 10, 2012 11:07 pm

Thank you. I think I understand. I haven't had to delve into that area yet.

Ian5913 · Post by **Ian5913** » Mon Jun 11, 2012 9:58 am

I have to say I know of at least three types. I think based on age.
They are simple but just be aware they can be different.

If I have this right there was, the first, that had just the bit between the engines bearings the stator. This was held in place by a bolt in the crankcase. The stator had a corresponding hole in its outer to locate the end of the bolt. It exhausted up a plain hole onto the drive chain.

Then they fitted a tube to hold the stator and act as an exhaust this fixed in the same position as the above versions exhaust hole but their were two types

one had the thread at the top near the outer face of the crankcase

The other is like the diagram (Engine view) that had the thread at the stator end.

I have this last version to hand.

The exhaust overall is 84mm long
Thread is 20mm long and is at the stator end.
The tube is about 10mm Dia
The inner hole (Exhaust) is about 4mm Dia

The Stator has a diameter of approx 50mm outer and 30mm inner and is 17mm wide

https://picasaweb.google.com/1050863888 ... 4682111010

I have posted a picture if it helps (Sorry better link now added)
IanEdited by - Dean5913 on 11 Jun 2012 09:02:45 AMEdited by - Dean5913 on 11 Jun 2012 09:08:58 AM

cbranni · Post by **cbranni** » Mon Jun 11, 2012 10:49 am

Thanks for that Dean, but its the rotor info I'm looking for, the stator is as you describe made from aluminium, the rotor is hardened steel and fits on the drive side axle tween inner races of bearings and I need to know its length.
cheers Colin

Ian5913 · Post by **Ian5913** » Mon Jun 11, 2012 11:21 am

With you now.

Its raining! Sheds 100ft away. Leave it with me.

Ian

Ian5913 · Post by **Ian5913** » Mon Jun 11, 2012 11:52 am

Here you go then.

The inner looks to be about 13/16ths (21mm)

The outer looks to be 1" 3/16th (30mm)

Its width is 11/16th (About 18mm)

Note inner slot and chamfered exhaust hole are in alignment on this one

Measurements are by eye I do not have an accurate gauge here.

Pictures available

Best wishes Ian

https://picasaweb.google.com/1050863888 ... 8ZGu0ZC5NQ#

cbranni · Post by **cbranni** » Mon Jun 11, 2012 12:09 pm

Thanks for that Dean your eye measurements are good enough for me, yours matches the one I have, I don't suppose you any idea what year engine this came out of?
Cheers Colin