BMW Airhead Tools

The standard BMW tool kit comes with a multitude of tools.

Some of them are quite specific and make maintenance of the bike much easier.

Here are some home made equivalent tools in case they are missing from your kit.

There are also some drawings for official BMW workshop tools.

Typical BMW tool kit

BMW tool number

This is a dog bone tool which has a 27mm box spanner on one end and a 36mm ring spanner on the other.

The ring spanner is for undoing the top fork nuts and the box spanner for adjusting the swinging arm lock nuts.

A replica 27mm box spanner can be made by slicing a standard box spanner and adding a handle.
Two things to note. Box spanners typically come in a 27/36mm combination or 24/27mm. The 24/27mm has a thinner wall section and will therefore more likely fit into the swinging arm recess.

Second, if you weld a simple handle across the centre of the spanner it prevents you using it in combination with an Allen key when locking the bolts down. Drilling off centre makes it a more useful tool.

Swinging arm spanner

The handle here was made from 8mm steel and knurled part way along.

When brazing or welding this tool, avoid the fumes which may contain chromium from the spanner metal.

The other end of tool can be replaced by using a 36mm socket on the fork top nuts.

However the nuts are very thin in section and they pull up flush to a washer so the socket must have no chamfer in it, otherwise is it likely to slip during use.

Original 36m socket

Most sockets do contain a chamfer on the leading edge so this should be ground off as square as possible, or preferably machined off in the lathe.

This socket has to tighten the fork nuts to a whopping 120Nm so it is important that it grips the nut as securely as possible.

Socket with chamfer removed

BMW Tool 00.2.560

This is a short ring spanner adapter to allow a torque wrench to be used to tighten the 12 sided bolts on the gearbox output flange.

There is not enough clearance in the Hook's joint to get a traditional socket on these bolts.

A similar tool can be made from a standard ring or combination 10mm spanner and a 1/2" to 3/8" socket adapter.

The distance between the centre of the ring spanner and the centre of the square drive should be as close to 44mm as you can get.

Parts for tool 00.2.560

The end of the socket adapter was machined off to leave a large flat area to weld to.

Then the spanner was welded in place as shown, with the welder turned up nice and hot.

Avoid the fumes from the welding.

This needs to be a strong joint to take the 42Nm of torque which is needed to tighten the nuts properly.

It is recommended that new bolts be used for this coupling every time they are removed and replaced. This is because they stretch when tightened to the full amount.

This is the BMW recommendation, however if you are facilitating a roadside repair and need to reuse the bolts, do them as tight as you can to avoid then coming loose in service, and replace as soon as possible.

The finished Tool.

BMW tool

This is a combination tool with a hook spanner on one end and a pin or peg wrench on the other.

The pin wrench is designed for removing the top filling caps on the front forks.

Before a replacement tool could be made, first the hole size in the caps was measured using a set of drill bits.

The hole diameter was found to be 4.4mm.

Two pieces of 5mm steel dowel were then turned down undersized (to about 4.2mm) so that the tool wouldn't be over constrained and a tight fit.

Each dowel was15mm long.

To get the spacing between the holes, the two dowel parts were inserted and the distance between them measured as shown.

Subtracting one dowel diameter gave the distance between the hole centres approximately.

Measuring hole spacing.

An old open ended spanner was chosen for the rest of the tool and this was drilled with two 5mm holes xxx.xxmm apart.

The two pins were then pushed into place on the arbor press.

Originally it was planned to supaglue the pins in place using the fork caps as a positioning guide, and then to weld them.

However they were a tight fit in the spanner such that glue as not needed.

After a check of the fit on both fork caps the pins were welded on the back side.

Pins welded in place

Finished tool, and tool in use (insert)

The clutch centring tool is
BMW Part  21-2-650

The drawing for the part is shown above. Click for a larger image.

This tool is used to insert a crank seal squarely into the engine housing and to the correct depth.
It is BMW Part 11-1-880 and the additional 3mm shim is 11-1-881

The drawing for the part is shown above. Click for a larger image.

This tool is used with the drift tool above to both remove and replace a crankshaft engine seal.
BMW Part 11-1-890

The drawing for the part is shown above. Click for a larger image.

This tool is used to stop flywheel rotation whilst undoing the flywheel or working on the crank.
BMW Part 11-2-800

The drawing for the part is shown above. Click for a larger image.

These bolts can be used to release the clutch spring in a controlled way.
BMW Part 21-2-600

The drawing for the part is shown above. Click for a larger image.

Tool used to hold the pinion on the final drive to enable shaft nut to be undone.

The drawing for the part is shown above. Click for a larger image.

Castlated socket for removing shaft seal behind final drive pinion.
BMW Part 33-1-700

The drawing for the part is shown above. Click for a larger image.

Simple plastic guide tool designed to help fit the fork damper piston into the stanchion, without damaging the piston rings on the threads.

The drawing for the part is shown above. Click for a larger image.

An STL file can be downloaded for 3D printing, by clicking the image below.

The tool should be used gently to avoid damaging the thread.
The inside can be polished to remove the printing layers, by using wet'n'dry paper and some water.