The Toolbox

Most of an airhead comes apart with ordinary metric tools and patience. What stops the job is never the socket set — it is the one purpose-made thing you do not own, discovered at the point where the engine is already in pieces.

This chapter separates the tools you need before you start from the specials you can buy when the job demands them. Prices drift; treat them as order-of-magnitude. The one rule worth stating plainly: buy the tool before you improvise, because on a forty-year-old casting the improvised version usually costs more than the tool.

Every figure on this page resolves to one model and year in the book. Pick your bike and the rows that apply to it come forward, with the rest marked.

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Must have — before you turn a single fastener

Tool	Why		Rough cost	Notes
Metric sockets & combination wrenches	everything	8–19 mm covers most of the bike	varies	Six-point sockets, not twelve, on anything that has been on the bike since Carter was president. Twelve-point rounds a soft head you cannot easily replace.
Hex (Allen) keys and sockets	covers, sump, calipers	6 · 8 · 10 mm do the heavy work	varies	Socket-drive hex bits beat L-keys for anything torqued. The sump plug and the timing cover will punish a worn key.
Torque wrench — two of them	heads, cases, fasteners	a low range and a mid range	varies	One wrench cannot cover valve-cover fasteners and head nuts honestly. A click wrench used near the bottom of its scale is a guess. See before trusting any of them.
Feeler gauges	valve clearance	metric blades, in good condition	low	Bent or burred blades read wrong. Two sets is not extravagant — one lives with the bike.
Multimeter	charging, ignition, everything electrical	DC volts, ohms, continuity	low	The single highest-value tool on this list per pound spent. Most airhead electrical mysteries end at a bad earth, and only a meter finds it.
Timing strobe	ignition timing	reads S and F through the window	low–mid	Static timing gets the engine running; only the strobe proves full advance is arriving. See .
Drift pin	BMW tubular wrenches, general	fits the holes in the factory wrenches	trivial	The factory part is 71-11-1-237-854. Some owners grind one end to a point and the other to a chisel and carry it as three tools. — listed not in the parts book but in BMW's own special-tools catalog, a separate volume (order no. 01 99 9 099 421 in the /5 era). The factory took its tools seriously enough to give them their own book.

The airhead specials — job-specific, and worth owning before the job

Tool	For		Rough cost	Notes
Clutch centering tool	clutch replacement	aligns the disc to the crank	~$25	Check the year before you order. The tool is sold in two versions — one for 1970–1980 airheads and a different one for 1981-and-later. They are not interchangeable, and the wrong one will let you bolt up a disc that is not centred.
Flywheel holding tool	clutch, rear main seal	blocks the crank against rotation	~$35	Snowbum puts it without qualification: under no circumstance should the flywheel or clutch carrier be removed on any airhead without first blocking the crankshaft. Improvising here damages things that are expensive to replace.
Valve spring compressor	head work	airhead-pattern, not a generic C-clamp	mid	Generic automotive compressors fit awkwardly around the rocker posts. The purpose-made version is the difference between an afternoon and an argument.
Star nut wrench	2V twins from 1970	the fastener nothing else fits	~$100	One of those items nobody buys until the day it becomes the only thing standing between them and the job.
Rod bolt tool	connecting rod bolts	1970-and-later twins	$25–50	Sold as a plain version and a HAZET version at roughly twice the price. Both do the job; the HAZET will outlive you.
Pinion gear holding tool	final drive	holds the pinion while you torque	~$80	See . The alternative is a helper and a lot of hope.
Gearbox flange puller	transmission	output flange removal	~$120	Buy or borrow. Levering a flange off with screwdrivers marks the sealing face and you will be chasing that leak afterwards.
Wrist pin press tool	pistons	press, do not hammer	~$120	Driving a pin through with a drift loads the rod sideways. This is the tool that protects a part you cannot buy new.

The swingarm pivot. Owners routinely turn down a socket on a lathe to reach the swingarm pivot fastener — it is one of the most commonly home-made airhead tools, and one of the few places where improvising is the normal answer rather than the reckless one.

Worth buying when the work gets deeper

Tool	For		Rough cost	Notes
Bearing separator & puller set	transmission, crank	gears and bearings off shafts	$200–370	The specialist versions are excellent and priced accordingly. A budget separator set plus patience covers a good deal of the same ground.
Shop press	transmission shafts, bearings	20 ton is ample	mid	A discount-tool press is genuinely adequate here — this is not a precision instrument, it is a controlled push.
Leak-down tester	rings vs valves	where compression testing stops	low–mid	Compression tells you something is wrong; leak-down tells you which component. Pairs with the screening figures in .
Dial indicator and depth micrometer	end float, shimming	the measurements that decide clearances	mid	Needed for crank end float and for factory-method shimming. Without them you are fitting parts and hoping.
Oil pressure gauge	diagnosis	running pressure, not the idiot light	low–mid	The warning lamp tells you when it is already too late. A gauge tells you the bearing story a year early.

Brands — where the money is worth spending

Category	Buy once		Good value	Notes
Hex & Torx drivers	Wera · Wiha · PB Swiss	the tool most worth upgrading	Bondhus	A worn hex key rounds a socket-head bolt, and a rounded bolt in a timing cover turns a one-hour job into a drilling operation. Wera's Hex-Plus profile bears on the flats rather than the corners — the single best-value upgrade on this list.
Sockets & wrenches	Hazet · Stahlwille · Gedore	the German workshop standard	Koken · Tekton · Sunex	Hazet turns up throughout airhead tooling — the rod bolt tool is sold in a plain version and a Hazet version at roughly twice the price. Koken (Japan) is the value pick that nobody regrets.
Pliers & cutters	Knipex	not a close contest	Irwin	Cobra water-pump pliers and their circlip range do things other brands only approximate. If one premium brand earns the premium, it is this one.
Screwdrivers — slotted	Wera · PB Swiss · Grace	hollow-ground, parallel-flank blades	Vessel	Airheads are full of slotted screws, and a tapered blade cams out and chews the slot. Hollow-ground blades sit flat in the slot — gunsmith sets are ideal. Keep an impact driver for the seized ones.
Torque wrenches	Tohnichi · Norbar · CDI	accuracy you can trust on a head	Precision Instruments	Buy calibrated, store at the lowest setting, and treat a dropped wrench as suspect until re-checked. See — a confident wrong number is worse than no wrench.
Pullers & separators	Kukko · Gedore	German, and what the specialists resell	generic separator sets	Kukko sets appear in airhead vendors' catalogues for good reason. For occasional work a budget separator plus a press covers much of the same ground.
Multimeter	Fluke	the one that never lies to you	Brymen · Klein · Uni-T	A cheap meter that reads 0.4 V low will send you chasing a charging fault that does not exist. Brymen is the value pick with real accuracy.
Measuring — micrometers, dial indicators, feelers	Mitutoyo · Starrett	shimming and end float	Fowler	These decide clearances you cannot see. Precision here is not vanity — it is the difference between a shim that is right and one that is nearly right.
Timing light	Gunson	reads the flywheel marks cleanly	Innova	An inductive pickup and a bright lamp is all this job needs. Advance-dial models are a convenience, not a requirement.
Press, stands, basic pullers	whatever is cheapest	a controlled push is a controlled push	discount tool shops	Deliberately included: this is where not to spend. Put the saving toward the tools that touch parts you cannot replace.

Read this as consensus, not specification. Tool brands are the most argued-about subject in any workshop, and the recommendations above are the ones that survive the argument — not the only defensible answers. The general rule holds better than any brand name: spend on what turns a fastener or takes a measurement, save on what only pushes.

Where to buy — and what to skip

BBoxer2Valve — the deepest catalogue of airhead-specific special tools, including the era-split clutch centering tools, flywheel holding tool, rod bolt tools and gearbox pullers.
CCycle Works — made many of the airhead tools in circulation. Worth knowing that their range has narrowed over the years, so some tools you will see referenced in older write-ups are no longer sold new. Second-hand ones hold value.
BBeemer Boneyard — clutch alignment tools and general airhead stock, with used parts alongside.
GGeneric discount tools — presses, bearing separator kits and basic pullers do not need to be specialist. Save the money for the tools that touch a part you cannot replace.

Do not bother. The classic BMW frame-mounted tyre pump is a nostalgia item — Snowbum reckons it can take an hour to inflate a tyre and risks bending the valve stem in the process. A cheap 12-volt compressor does the job in a fraction of the time.

The Toolbox

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