Inner Chaincase clutch shaft seal

Information relating to the Matchless G5 or AJS Model 8 350cc Lightweight
Locked
Jam23a30
Posts: 13
Joined: Tue Aug 20, 2019 12:28 pm
Location: UK

Inner Chaincase clutch shaft seal

Post by Jam23a30 »

Just using the lockdown to invest some time in my new to me G5.

I see a mighty engine oil leak from what looks like the seal at the back of the clutch. Having taken the clutch off I'm faced with a splined shaft protruding through a pressed steel plate which I guess contains a seal and the whole pressed plate moves with the gearbox when adjusting the primary chain.

Can anyone tell me how the pressed steel plate is fixed, do I need to remove the inner chaincase to remove the seal and is a replacement seal available, I can't pick up the details from the engine diagram I have

Many thanks in advance

Andy
User avatar
Ozmadman
Posts: 2651
Joined: Wed Dec 14, 2011 1:02 am
Location: ESSEX UK

Re: Inner Chaincase clutch shaft seal

Post by Ozmadman »

The plate is fixed in the chain case and it isn't a seal but just a felt ring which really does nothing more than stop dirt from getting into the chain case. It is also a bugger to replace as the replacement felt seems far too thick to force into that plate and you will end up having to remove the casing unless the gearbox is already out where you may stand a chance doing it in situ. I ended up trimming mine down to get it t fit. Don't think much oil if any gets past it from the chain case. The real leak will be front the gearbox output shaft seal.
Last edited by Ozmadman on Sun Apr 05, 2020 5:54 pm, edited 1 time in total.
Paul
1960 Model 8
1974 Yamaha RD250B US Model 6 speed
SPRIDDLER
Member
Posts: 8542
Joined: Wed Sep 01, 2004 1:00 am
Location: WEST SUSSEX UK

Re: Inner Chaincase clutch shaft seal

Post by SPRIDDLER »

I'm not familiar with L/W's but if it's any interest or future use here's an exploded drawing with part nos. of the L/W engine, clutch and g/box.

http://archives.jampot.dk/technical/Cut ... _Parts.pdf

Happy to be contradicted as I'm just passing Lockdown time. :)
'There is a tide in the affairs of men
Which taken at the flood............'
Jam23a30
Posts: 13
Joined: Tue Aug 20, 2019 12:28 pm
Location: UK

Re: Inner Chaincase clutch shaft seal

Post by Jam23a30 »

Thanks, I suspected an engine oil leak since I'm getting some old black oil dripping from the fully enclosed chaincase. I took the chaincase off to inspect the clutch and found the clutch centre to be loose which reading posts on hear seems a reasonably common issue.

I think I will refit clutch and outer chaincase, see how she performs on the road and monitor gearbox oil level before going any deeper. At least the rear chain is well lubricated!

Andy.
User avatar
Ozmadman
Posts: 2651
Joined: Wed Dec 14, 2011 1:02 am
Location: ESSEX UK

Re: Inner Chaincase clutch shaft seal

Post by Ozmadman »

Just keep that gearbox topped right up to the filler level. All of the gears are at the top of the box so damage can be done if the oil level is allowed to drop too low. One thing to look at...see if you have any oil running down the centre stand legs, a further indication of a gearbox oil seal leak and if you can get under the bike to see or get your hand up under the front section of the chain guard you can feel the open end of the front of the box and if there is a leak there you will get cleanish oil on your hand..
Paul
1960 Model 8
1974 Yamaha RD250B US Model 6 speed
vigo
Member
Posts: 114
Joined: Sat May 18, 2019 5:50 pm
Location: Cheshire UK

Re: Inner Chaincase clutch shaft seal

Post by vigo »

Well Andy having owned my g5 also for less than a year and ridden only recently a few test miles my story is similar. Oil down the centre stand from gearbox area, don't think the oil was black though. Anyway, as winter '19 loomed I decided to pull the gearbox.
To prevent going over old ground which can be found in forum I will in summary say it was the gbox leaking from pretty much everywhere. I replaced several internal needy parts, bush, bearing etc and the end result is no static leaks and only small drips after a ride. This oil is probably leaking from between sleeve gear (which turns) and metal ring that seats main seal, which doesn't turn.
On the whole very satisfying and I learned a lot, members on the forum are a great help.

Sent from my SM-T580 using Tapatalk
Locked