Hello from Down Under. Just got a 1947 G80L

Information relating to the Matchless G80 or AJS Model 18 500cc Heavyweight.
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Re: Hello from Down Under. Just got a 1947 G80L

Postby Mick D » Sat Sep 15, 2018 10:42 am

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

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

Postby WnRn » Sat Sep 15, 2018 12:00 pm

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)

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

Postby WnRn » Sun Sep 16, 2018 10:34 am

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

Postby clanger9 » Sun Sep 16, 2018 1:34 pm

Is there a piece of the 2nd compression ring missing? Maybe budget for a new set of rings... ;)
1966 AJS Model 14 250 CSR "cafe racer"
1993 Ducati 750SS

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

Postby WnRn » Wed Sep 19, 2018 9:44 am

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)

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Posts: 17
Joined: Sun Sep 09, 2018 10:27 am
Location: Australia

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

Postby WnRn » Wed Sep 19, 2018 9:47 am

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

Postby cfaber » Wed Sep 19, 2018 5:01 pm

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.

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

Postby clanger9 » Wed Sep 19, 2018 9:23 pm

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...)
1966 AJS Model 14 250 CSR "cafe racer"
1993 Ducati 750SS

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

Postby WnRn » Fri Sep 21, 2018 10:41 am

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)

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Posts: 17
Joined: Sun Sep 09, 2018 10:27 am
Location: Australia

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

Postby WnRn » Sun Sep 23, 2018 3:16 am

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)

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