On another thread, the subject of using the correct wrenches came up. Since some folks' introduction to 1/2A was by way of a bargain Sure Start, they may not know that wrenches even exist.
Pics 1 and 2 show how the wrench is used to remove or tighten the cylinder on a Sure Start.
Pic 3 shows that you should use two wrenches to remove or tighten the glow plug.
Before cylinders had slots on top, cylinders were removed and tightened by inserting the slotted end of the wrench in the exhaust ports. Be very careful when doing this and make sure the wrench is inserted as far as it will go. Mishandling can cause a burr that is a pain in the neck to fix. Two wrenches were used to remove the glow head with these too.
At some time the transfer ports were enlarged which necessitated an increase of slot size. The wrench in pic 4 works on the Space Bug Junior but will not fit on the Black Widow cylinder. Pic 5 shows the old size on the left and the newer size on the right. Be VERY careful if using a newer wrench on the older cylinders.
While checking this stuff out, I noticed that if using the slot for the upper cylinder on the SS cylinder, I must remove the needle valve, otherwise I may break it off. Note in pic 6 how close the wrench is to the needle. This may not be a problem on your engine...depends which way the slot is positioned. You only need to move the wrench about 1/4 turn, then it can be turned by hand.
Some wrenches have the large slot on the side. I could not get that one on without removing the needle (pic 7).