Three decades after the last of these bikes left Berlin, parts availability remains extraordinary — provided you search the way the trade searches. That means by part number, always, sourced from the fiche for your build date rather than your model year.
What follows is a map of the whole supply landscape: the dealers who still stock genuine parts, the specialists whose aftermarket versions improve on the originals, the breakers who hold what nobody makes any more, and an honest note about which systems are getting hard to feed.
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.
Open this chapter in the book| Step | Do this | Where | Notes | |
|---|---|---|---|---|
| 1 · Identify by part number | RealOEM fiche → exact BMW p/n | check your build date, not model year | realoem.com | The fiche splits at production changeovers (9/80 especially — see the timeline). The p/n is the universal key every vendor speaks; never shop by description alone. |
| 2 · Price the OEM route | MAX BMW fiche-to-cart · Bob's BMW · Sierra BMW | — | dealers w/ deep airhead stock | BMW still stocks a shocking amount for these bikes. MAX's clickable fiche is the fastest; Bob's curates airhead service kits that bundle everything a job needs. |
| 3 · Check the specialist aftermarket | often better than OEM | see Vendor Directory in Upgrades | EME · Boxer2Valve · Siebenrock… | Charging, ignition, cylinders, shims, tools — the specialist part frequently improves on the original (and the NLA gaps below are where they live). |
| 4 · The used/NLA path | BeemerBoneYard · Martindale MW · Bob's used dept · eBay by p/n | — | when new is gone | Search eBay with the exact part number, not words. Buy used measuring parts (cylinders, cranks, gears) only with dimensions in hand — this app's wear limits are your checklist. |
| ⚠ Re-Psycle is closed | shuttered Dec 2023 after 46 years | — | Lithopolis, OH | Still recommended all over old forum threads — don't chase it. No single supplier replaced it. BeemerBoneYard, Martindale and Bob's used department each cover part of what it did — check what each actually stocks for your part rather than assuming any of them is a direct used-airhead breaker. |
| System | Still easy | Watch items | Go-to | Notes |
|---|---|---|---|---|
| Engine internals | bearings, thrust washers, rod bolts, full gasket sets | early one-off variants | OEM · Boxer2Valve | Gasket availability is superb — buy complete sets, always renew crush washers. |
| Cylinders & pistons | pre-'81: +0.25 rebore pistons · '81+: Siebenrock kits | good used Galnikal barrels = rare | Siebenrock · BeemerShop | Never buy used plated cylinders unmeasured. The Siebenrock Replacement Kit is the clean '81+ answer (see Upgrades §Siebenrock). |
| Heads & valve gear | valves, guides, seats, springs, rockers | cracked heads → weld repair territory | Long's · BeemerShop | Guides/seats come oversized — head work is a machine-shop job, and the two PA specialists are the reference. |
| Carburetion (Bing CV) | every jet, needle, diaphragm, float, gasket | carb BODIES: used market only | Bing Agency · Boxer2Valve | Bing still supports these fully. Worn slides/bodies → hunt matching numbers used (flange stamp!). |
| Electrical & charging | everything, stock or upgraded | grey Bosch coil (buy the fix, not another) | EME · Motorrad Elektrik | Best-supported system on the bike. Repro harnesses available per model. |
| Ignition | points, condensers, advance springs, electronic conversions | bean-can (Hall) units: rebuild services vs NLA new | EME · Boxer2Valve | '81+ Hall cans get rebuilt or replaced by aftermarket (EDL-IGNS etc.). |
| Transmission | bearings, seals, shims (Oilhead sizes substitute) | GEARS & shafts: mostly used market | Cycle Works · used | Buy a whole donor box before hunting single gears. Shim kits + measuring plates: Cycle Works (see Trans §shimming). |
| Driveshaft & final drive | boots, seals, bearings, U-joint bolts | crown/pinion SETS: scarce — matched pairs only | OEM · used complete units | When a gearset dies, a complete used final drive (check ratio stamp!) usually beats sourcing a matched set. |
| Brakes | pads, rotors, master/caliper rebuild kits, braided lines | ATE swinging-caliper small parts thinning | OEM · aftermarket | Custom-length stainless lines made to order by the usual line houses. |
| Suspension | fork seals, bushings, springs, damper parts · shocks aftermarket | — | Progressive · Ikon · Hagon · YSS | Nobody rebuilds 40-year-old stock shocks — replace and match rates to café weight. |
| Wheels & spokes | spokes/nipples custom-cut, rims, bearings, seals | snowflake cast wheels: used only, check for cracks | Buchanan's (spokes) · used | Buchanan's cuts stainless spoke sets to any hub/rim combo — the wheel-lacing standard. |
| Bodywork | repro fenders, seat pans/covers, badges & decals | tanks: used, repro, or alloy custom | Hammersley (badges) · WBO (alloy tanks) | Used tanks: inspect inside with a borescope; sealer jobs hide sins. |
| Cables & controls | complete repro cable sets, levers, grips, switchgear | early switch clusters | Boxer2Valve · Euro suppliers | Custom-length cables available for café bars — measure before ordering. |
| Exhaust | full repro systems, headers, mufflers, finned nuts | — | multiple makers, EU & US | New finned nuts + fresh anti-seize beat wrestling seized originals (see Torque §18). |
| Hardware & fasteners | stainless kits, every metric size | — | Rocky Point (SS kits) · BelMetric · McMaster | Exceptions that must stay OEM: rod bolts, flywheel bolts, rear-wheel bolts, U-joint bolts. |
| Special tools | exhaust-nut wrench, clutch tools, shim plates, pullers | — | Cycle Works · EME | The exhaust-nut wrench and swing-arm socket pay for themselves the first job. |
| Literature | Clymer & Haynes in print · factory manual + parts-catalog reprints | — | Boxer2Valve · Bench Mark Works | Plus the free canon: Snowbum's site and — ahem — this app. |
| Source | Specialty | Region | Notes | |
|---|---|---|---|---|
| Motobins · Motorworks | full-line airhead parts houses | — | UK | The two long-standing UK mail-order institutions — often the price check against US vendors. |
| Motorworks | full-line airhead house, est. 1989 | new · used · reconditioned | Huddersfield, UK | Their parts finder filters by production window — an '81 R100 returns ~2,700 fitting parts, around 590 of them used. That used counter is the answer to this book's scarcity list: gearbox internals, crown-and-pinion sets, switchgear. Stocks EnDuraLast, Siebenrock, Odyssey, Ikon, Hagon, Goodridge, Venhill, Tri-Spark. Mail order only, no counter. |
| Motobins | the other UK institution | — | UK | Long-standing mail-order house; worth a price check against Motorworks. |
| De Hobbyist | Dutch BMW specialist & wholesaler | retail + B2B | Hunsel, Netherlands | Boxer parts, Ikon shocks, Krauser, Wunderlich, Sachs, post-'1 fork components, tools, and bundled service kits. A useful third quote from inside the EU — and the natural supplier once the Spain plan lands. |
| Uli's Motorradladen | vintage & classic BMW parts | — | Germany | Deep vintage stock at the source. |
| Siebenrock | engine kits & parts | — | Germany | Direct or via US dealers (BeemerShop). |