Hello from Down Under. Just got a 1947 G80L

Information relating to the Matchless G80 or AJS Model 18 500cc Heavyweight.
Mick D
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Joined: Mon Mar 24, 2014 5:44 pm
Location: Aberdeenshire

Re: Hello from Down Under. Just got a 1947 G80L

Post by Mick D »

Hi

The damage to the piston crown looks to me like it was caused by the inlet valve dropping and subsequently bending, I'd have a good look at the valve stem and guide.

Regards Mick
WnRn
Posts: 17
Joined: Sun Sep 09, 2018 11:27 am
Location: Australia

Re: Hello from Down Under. Just got a 1947 G80L

Post by WnRn »

Mick D wrote:Hi

The damage to the piston crown looks to me like it was caused by the inlet valve dropping and subsequently bending, I'd have a good look at the valve stem and guide.

Regards Mick
The inlet valves looks like it is not seating at all. Getting a valve spring compressor off a mate and will take both valves out and check them.
Cheers Ross.

My motorcycle blog..... http://rossmz.blogspot.com/

The chief enemy of creativity is common sense (Pablo Picasso)
WnRn
Posts: 17
Joined: Sun Sep 09, 2018 11:27 am
Location: Australia

Re: Hello from Down Under. Just got a 1947 G80L

Post by WnRn »

Used the dating service that the club offers. My frame is 1950.

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No doubt about the engine.

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Cheers Ross.

My motorcycle blog..... http://rossmz.blogspot.com/

The chief enemy of creativity is common sense (Pablo Picasso)
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clanger9
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Joined: Sat Jun 20, 2015 9:38 am
Location: Chester, UK

Re: Hello from Down Under. Just got a 1947 G80L

Post by clanger9 »

Is there a piece of the 2nd compression ring missing? Maybe budget for a new set of rings... ;)
1989 Moto Morini Dart 350
1993 Ducati 750SS
WnRn
Posts: 17
Joined: Sun Sep 09, 2018 11:27 am
Location: Australia

Re: Hello from Down Under. Just got a 1947 G80L

Post by WnRn »

clanger9 wrote:Is there a piece of the 2nd compression ring missing? Maybe budget for a new set of rings... ;)
Its broken in 2. So new rings are in order.
Cheers Ross.

My motorcycle blog..... http://rossmz.blogspot.com/

The chief enemy of creativity is common sense (Pablo Picasso)
WnRn
Posts: 17
Joined: Sun Sep 09, 2018 11:27 am
Location: Australia

Re: Hello from Down Under. Just got a 1947 G80L

Post by WnRn »

In no way is this bike going to be a full restore. Fix what needs fixing in the engine. Do a makeover.

Lets see if I can get this BSA Firebird scrambler fiberglass tank to fit on the Matchless.... As a precaution may seal the inside with Caswell Expoxy Tank Sealer. I have read it works very well with fiberglass tanks and modern fuel does not eat the epoxy coating. With BC comic Grog.

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Cheers Ross.

My motorcycle blog..... http://rossmz.blogspot.com/

The chief enemy of creativity is common sense (Pablo Picasso)
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cfaber
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Joined: Mon Nov 20, 2017 5:37 am
Location: USA, Colorado
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Re: Hello from Down Under. Just got a 1947 G80L

Post by cfaber »

One thing to note is that with the fiberglass tank if it's ever had fuel in it you'll likely never be able to seal it successfully. The fuel leeches into the tank and prevents adhesion. The only time I've seen a sealing job end successfully is when the tank is cut in half reglassed / gel coated then reassembled. After that the seal sticks nicely.
Fix it until it's broken!

Otherwise how will
anything get done?
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clanger9
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Joined: Sat Jun 20, 2015 9:38 am
Location: Chester, UK

Re: Hello from Down Under. Just got a 1947 G80L

Post by clanger9 »

My fibreglass tank is lined with Caswell and it's been fine for a couple of years. No sign of any problems yet (fingers crossed...)
1989 Moto Morini Dart 350
1993 Ducati 750SS
WnRn
Posts: 17
Joined: Sun Sep 09, 2018 11:27 am
Location: Australia

Re: Hello from Down Under. Just got a 1947 G80L

Post by WnRn »

The BSA Firebird scrambler fiberglass tank has now set the direction this build will go in. Inside of tank will get treated with Caswell epoxy liner. Need to make mounts that come off the original
frame's mounts so tank sits level.

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Cheers Ross.

My motorcycle blog..... http://rossmz.blogspot.com/

The chief enemy of creativity is common sense (Pablo Picasso)
WnRn
Posts: 17
Joined: Sun Sep 09, 2018 11:27 am
Location: Australia

Re: Hello from Down Under. Just got a 1947 G80L

Post by WnRn »

Valves are out. Both seem ok!? Will do further checking of them. Inlet was held in by surface rust and spider webs. They both look like they are not original. Clean up of head and valves then lap the valves in.

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Cheers Ross.

My motorcycle blog..... http://rossmz.blogspot.com/

The chief enemy of creativity is common sense (Pablo Picasso)
Locked