AJS & Matchless Owners Club

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

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.

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



No doubt about the engine.

Is there a piece of the 2nd compression ring missing? Maybe budget for a new set of rings...

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.

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.

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.

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...)

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.

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.