Hydraulic Jacks – Airheads Beemer Club

Inexpensive yet very useful hydraulic jacks…
for use in servicing your BMW Airhead motorcycle

Above are two inexpensive ‘bottle jacks’. A 12 inch tall ‘carpenter’s square’ is in the center of the photograph, and a 12 inch ruler below to give you an idea of size. These two jacks happen to be the versatile types that have tops that screw-down into the jack pistons and those jack pistons are shown with jack pressure released, that is, down/collapsed.

Making an anvil if your jack does not have a particularly useful one, as in the photo, can be simply made from a piece of iron pipe, cut with a hacksaw to make a half round length. This can be much nicer than the bent metal type in the right side of the above photo that I made in a couple of minutes. The hacksaw-cut type is also described in this article. The jack on the left has a top I made from aluminum stock.

Below is a photo of my small scissors jack. It is rated at 2 tons. I find this jack quite useful. I have made a curved cradle for the anvil top of this jack, as shown. As on my other jacks, the curved cradle is rotatable. This jack cost only a few dollars more than the inexpensive bottle jack type I discuss in this article. Note how small this floor jack is….and it is also not very tall.

To make useful jacks for all sorts of work on your BMW motorcycles, I suggest you purchase a small scissors jack as shown, and also purchase the smallest (lowest height) hydraulic bottle jack, all at your nearest auto-parts store, WalMart, etc. For the best versatility, if you have a choice, get the shortest bottle-jack, and the type that has a screw top that you can extend upwards.

The bottle jacks packaging boxes typically list approximately 6 inches of possible lift movement for the bottle jacks. In actuality, for the one’s I have seen, their hydraulic piston will move a bit under 5 inches. These jacks sell for $15 or so, and every one I have seen is made in China but I have yet to see any of them leak or otherwise fail.

Bottle jack: Start your conversion process by unscrewing the top threaded extension part to its upper limit, if it has such a threaded top part (which I do find useful). This will minimize the welding heat (if using a welder) getting into the jack (do wrap the top threads with wet rags).

Obtain a piece, several inches long, maybe 4″, of iron pipe (but, read the entire article here…you might want another material or size). I suggest the inside diameter of that pipe to be such that after you cut it, it fits under and slightly around, but not at all snugly, at any frame or swing arm round tubing areas that you might use it at. In particular, have your piece of pipe, as cut, fit the ‘crossover’ at the forward area of YOUR Airheads’ swing arm.

Most Monoshock Airheads have a larger diameter crossover than other models, and you will want to measure yours, and I suggest you make your jack fit all your Airheads. A couple of inches or slightly larger pipe diameter seems OK on the non-monoshock models though.

Cut the piece of pipe LENGTHWISE to make two halves. The halves need not be equal, and you can, if you want-to, cut with a bias towards one side. There is also no need to have your pipe adaptor grip the bike crossover. Clean-up one of these halves …that means smooth and round the sharp edges. Weld or bolt, or?….that half to the top of the jack, keeping the top threaded part of the jack cooled with a wrapped water-soaked rag if welding…..weld such that the curved piece will be SQUARELY welded to the top. …..be SURE it is squarely welded, and when you have tack welded it and adjusted it to be square, then weld it all around for good strength.

Some bottle jacks tops can be drilled and tapped and an aluminum pipe or other piece used. Some jack tops are a rotatable anvil unit, and that may even be on a threaded shaft that can be adjusted for height. I find those jacks generally the most versatile. I suggest you do not weld your adaptor to the jack anvil if the anvil does not rotate, but you may consider it.

Just one use for these types of jacks would be to slightly jack up the round tubing rear cross-member, to enable you to move the rear tire a small amount off the floor. Very handy when wanting to rotate the rear tire such as to rotate the engine when setting valves, ……..and many other chores.

You may need a sturdy piece of wood to have the jack high enough. I have found a 1 inch piece of plywood, and a piece of 4 x 6, to be just right for most Airheads. On one of these many jacks I have modified, I put holes in the corners to enable sturdy mounting of the jack to studs sticking up from various pieces of wood. Let your imagination work for you. I also have small pieces of wood to use at the top of my jacks for various purposes.

Some may prefer to use a taller jack to begin with, with a larger base to the jack (or, make a base), but if the minimum bottle jack height is too tall, you may have troubles using your jack.

The first photo contains two relatively recently-made jacks. Neither one has the iron pipe as described, because after some begging, I gave away my last of the iron pipe ones. The photo’s jack on the left has a undercut (spot faced depression, hidden from view here) under the milled aluminum piece, and a central hole, and I drilled and tapped the jack top piece. It is way overly-fancy. The jack on the right was one I made up in a few10 minutes, and it is crude, but functional. If you make up some sort of jack like these, consider if you need a much larger base, perhaps of heavy metal or maybe a foot square piece of plywood, if so, perhaps bolt the jack to it.

You may find use for a floor jack as shown in the other photo, even a larger conventional low floor jack, etc., depending on your bike. For a late model Airhead with the exhaust collector chamber, that chamber is going to prevent you from using the frame cross piece. A jack under the exhaust collector, with a piece of wood, works fine. Many of you have conventional or low-boy large size jacks, if they do not work for you on the motorcycles you own, why not consider the jacks in this article!

Items also not shown are pieces of wood that fit the top of these jacks …and make the top of the jack a flat surface …so the jack can be used at places like the oil pan, etc, without damaging any fins, etc.

Revisions:
12/17/2019: Transfer, edit for airheads.org, initial uploading.
02/23/2021: Minor clarifications and check http>https.

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