AJS & Matchless Owners Club

First post to the forum so forgive me if I'm posting in the wrong place.
On my 1953 Model 18 there is an oilway from the crank bush up to the top that allows oil into the bore. I can see many pictures in the manuals of this and understand that when I get a rebore (It was the original wire wound piston) I'll probably have 5 thou clearance and this oilway is then not too important but I would like to get the ball valve and spring out to check them and maybe keep this oil passageway in use.
How do I get them out? I was expecting to put a small flat head screwdriver down and feel for the slot to remove a small keeper for the spring but I can't feel a slot.
The small thread is most likely a BA size but a 4mm fits not too bad should something be screwed down and then pulled to release the inner part? I've included the picture here.http://www.jampot.com/forum/download/fi ... ew&id=7897

Hi, there is general agreement that this oilway is not necessary. It was deleted around 1956, presumably for this reason. I have a '54 18S, and the engine was rebuilt by the late Malcolm Saggers, one of the best engineers around; he removed the brass bush you can see and blocked the oilway with, I believe, a 3BA screw. This is recommended as the oil goes from the bush to a groove round the base of the barrel to holes in the bore to lubricate it. In theory oil in this groove could leak out of the join between barrel and crankcase. I would block your oilway up and not bother with checking the valve, with modern oils a separate feed to the bore is even more unnecessary and I have never heard of a piston seizing due to lack of oil from this feed. What do others think?

Welcome to the Forums, David.

Yes, 3 BA screw and lever out. See page 10 here:

http://archives.jampot.dk/technical/Spe ... hanics.pdf

I removed that oil feed bush, ball and spring on my '54 as the replacement barrel didn't have the oil galleries of the original. I didn't block it but just used the cylinder base gasket without the cut-out for the oil feed. No leaks and no seizures in 000's of miles, but no reason why it shouldn't be blocked off if you want to be sure of no leaking.

Thanks guys. It's great to know folks have done this before. I might be asking more questions as the rebuild continues.

Use a 4ba screw (I believe thats the size), scew it almost all the way in and then using 2 flat screwdrivers evenly pry the screw out. If it's really stuck a little heat. It's just a tapered brass barrel. Then a magnet or gravity to remove the ball and spring. Extremely easy to check and clean.