Primary sprocket part

Information relating to the Matchless G2 or AJS Model 14 250cc Lightweight
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Ernie green
Posts: 12
Joined: Thu Aug 24, 2017 9:20 am
Location: TYNE AND WEAR UK

Primary sprocket part

Post by Ernie green »

Hello everyone I am after some info on my g2 250 ,59 model .i was looking at my manual of the engine and noticed a part it's either a spacer or an oil seal behind the primary side engine sprocket .the part no is 041091 but it's not in any parts listing on the club spares and it's not even listed on Russell motors site .ther isn't any on mine and I think the oil is leaking through,so that means crank seals and I know what that entails I was hoping someone might know about this part,any info would be greatly appreciated, thanks .ernie g
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clanger9
Posts: 1165
Joined: Sat Jun 20, 2015 9:38 am
Location: Chester, UK

Re: Primary sprocket part

Post by clanger9 »

Hi Ernie,

There's no seal behind the crank sprocket - it is unlikely that any oil would build up here anyway.
The spacer you mention isn't available anywhere and it seems that most Lightweights do not have this spacer fitted.

The role of the spacer (if fitted) is to line up the sprocket with the primary chain.
I had to improvise a spacer on my bike to cure a misalignment here.

A bit more info in this thread: http://www.jampot.com/forum/viewtopic.php?f=15&t=17322
1989 Moto Morini Dart 350
1993 Ducati 750SS
Ernie green
Posts: 12
Joined: Thu Aug 24, 2017 9:20 am
Location: TYNE AND WEAR UK

Re: Primary sprocket part

Post by Ernie green »

Might get a spacer if i need one just renewed the gearbox seal and started the bike up there is oil leaking from the bottom of the inner cover on the primary side I didn't think there was oil in there I stripped it down again and the only place I thought it would come from was through the bearing behind the engine sprocket. The gearbox seal seems fine no oil leak .and there is no gaskets for the inner and outer chain case just used gasket seal .
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clanger9
Posts: 1165
Joined: Sat Jun 20, 2015 9:38 am
Location: Chester, UK

Re: Primary sprocket part

Post by clanger9 »

Is the inner primary cover fastened on tight? It's only held in place with six small screws and these can work loose.
There is also a small gasket (042169) between the inner primary cover and the crankcase to prevent oil leaking from the joint.
1989 Moto Morini Dart 350
1993 Ducati 750SS
Ernie green
Posts: 12
Joined: Thu Aug 24, 2017 9:20 am
Location: TYNE AND WEAR UK

Re: Primary sprocket part

Post by Ernie green »

Oh I never new that there was not any on when I stripped it down ,I got a full gasket set so might be in there, thanks for this priceless info many thanks ,
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