I honestly have been working on my AJS. I picked it up in October of 2010 and was all gung-ho to get it cleaned up and on the road.
But you didn’t hear anything. Nothing.
But believe me, I have been working on it. Honestly. The problem is that to this point there hasn’t been much to say or to show. I’ve been reading. A lot of reading. It’s a different beast than the V-Twins or Inline-Four’s I’m used to working on. It’s a push-rod engine with a dry sump for oil (dry sump engines carry their oil in an oil tank that is separate from the engine and uses two pumps to lubricate – one to pump oil to the engine, where it lubes everything and then drops to the bottom of the engine, and a second or ‘scavenge’ pump which pumps the oil back to the oil tank). This is something a Harley fan might be used to, but I’m not overly familiar with the 50+ year old technology …
I located a local importer and distributor of original parts from the UK (Walridge Motors). I procured factory manuals, parts schematics, and a plethora of tips from other AJS/Matchless owners.
Now I’m starting to have something to show you.
I started with the easy task of cleaning the Amal carb and replacing the throttle and clutch cable (Yes, that is an Easy Rider poster in the background!). First step was removing the fuel line running from the tank – I will also be replacing the fuel line, but haven’t got around to buying any yet. There is also an overflow line that must be removed (visible in this picture). The carb is attached to the engine via two bolts on either side of the carb and is buffered by a rubber gasket of sorts. Once you remove these two bolts the carb wiggles off and is free of the engine. To completely remove the carb we must detach the throttle cable (and with this carb the choke cable as well). There is a cap on the top of the carb that can be twisted off and will free the throttle slide and the choke. The carb can now be removed.
By removing the three screws on the ‘Amal’ cover plate you have access to the float – on newer carbs the float is usually on the bottom. This is the first thing I took apart. The float itself is held in with a brass ring (often called a ‘pin’) that just slides off, then the float can be removed. On this carb the needle rests on the float so it slid out upon removing the float. Now the jets can be removed.
Jets are screws that have a hole through the center of them which the fuel flows through to mix with air. The main jet is short and fat and will have a flat screwdriver head. The pilot jet is long and skinny and will take a flat head screwdriver to remove.
The last step before actually cleaning the carb is to remove the parts on the outside. The air screw and the idle screw can be removed with a flat head screwdriver. The idle screw is the larger of the two, and it adjusts the idle rpm of the engine. Also remove the air screw, which is the smaller screw and adjusts the air flow through the carb when the engine is running.
Before I started cleaning the carb I carefully removed all gaskets and o-rigns – all were in great shape and appeared to have been recently replaced, so I deemed it unnecessary to replace them. Plus I’m a cheap bastard.
The easiest way to clean the carb and the parts is to soak them in carb/parts cleaner. Follow the instructions on the can for cleaning. I used a spray can of carb cleaner and used a clean oil drain pan to soak them in. Be sure to wear safety glasses and gloves!
I scrubbed the parts with a wire brush and then sprayed with carb cleaner. Then I sprayed the cleaner into the holes that the jets, air and idle screws, float needle, and choke came from. When cleaning the jets, be sure to spray cleaner into the holes, and look through them into light to make sure the hole is cleaned. If jets are not completely clean, blowing compressed air through the hole will remove any debris.
Allow everything to dry then replace gaskets/o-rings. Replace all parts in the opposite order as when you removed them. When installing the air screw (the skinny screw), if you don’t have a setting from the factory I usually screw it in all the way then back the screw out a turn and a 1/4. When the engine is running and warm you can properly adjust it by turning the screw in till the engine stumbles, then out till it stumbles, and leave it at half way in between.
Next install the float. To install the float, line the holes up with the holes in the carburetor and slide the float pin in. The pin will slide around freely, just make sure it is centered so it is secure. To make sure the float needle is working properly, move the float up and down to make sure the needle moves freely. If the needle gets stuck in the up position it needs to be replaced.
Now I put a new throttle cable and choke cable in the throttle slide and choke slide. This was a matter of convenience as the carb must be removed to replace them. I still need to purchase new handlebar grips for the throttle…
With the throttle slide in and choke slide in, you can set the idle screw. Slowly turn the idle screw until the throttle slide begins to move. Now turn the screw half a rotation. You can properly adjust the idle screw with the engine running – turn the idle screw in to increase idle, turn it out to decrease idle.
Then I put the carb back on the bike by ‘wiggling’ it back on the rubber boot and bolting it back on. Now it looks cleaner than the rest of the bike!
Next I’ll be working on replacing oil, fuel line, spark plug, drum brake shoes, and rubber and getting this bad boy back on the road! I’ll keep you posted!