There is a version of this hobby where originality is the point, and this chapter is not for it. This is for the rest of us — the people who want a motorcycle of this age that starts on a cold morning, charges at a traffic light, stops in the wet and does not electrocute itself when the loom finally gives up.
The good news is that the airhead aftermarket is unusually mature. Charging systems that make three times the original output, ignition that never needs a feeler gauge again, control electronics that replace an entire relay board with something the size of a cigarette packet, cylinder kits that answer the no-rebore problem outright.
Each entry below notes what it actually buys you and, more importantly, what else it forces you to change. Nothing on a motorcycle gets upgraded alone.
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| System | Output | Architecture | Fits | Notes |
|---|---|---|---|---|
| EnDuraLast 450 (EDL4) | 450 W / 32 A @ 14 V max | PM rotor + hi-output stator (Ducati Energia), brushless | all airheads, 1969–1996 | Curve: 280 W @ 2000 · 350 W @ 3000 · 400 W @ 5000 rpm — up to 80% over stock Bosch. Replaces rotor, stator, diode board AND regulator as a set; combined reg/rect mounts remotely for cooling. No brushes, no slip rings, and immune to the burnt-GEN-lamp no-charge failure. /5 models need a starter-relay mod. Snowbum's independent testing: ~450–500 W at cruise, strong output barely above idle. |
| EnDuraLast 4Li (EDL4Li) | 450 W, lithium-tuned regulation | same PM hardware | LiFePO4-equipped bikes | The right variant for lithium batteries — regulation matched to LiFePO4 charge profile. Never pair a lithium battery with an old mechanical VR. |
| EnDuraLast III (EDL3) | 400 W / 28 A, uprated Bosch-style | larger-Ø rotor + stator, new diode board + VR | by stator diameter, not "all" | For purists keeping the excited-field architecture — stock GEN-lamp behaviour, stock look, more headroom. Two kits, and they are not interchangeable: EDL3-107 for the 107 mm stator (/7 and later, 1977–1995) and EDL3-105 for the 105 mm /5 and /6 bikes. Measure the stator or read the Bosch number off the existing part before ordering — model year alone will mislead you on a bike that has had a front end apart. |
| Sizing rule | demand + 10–20% buffer | at YOUR cruise rpm | any system | Sum every accessory (heated grips, LED aux, m.unit loads) against output at the rpm you actually ride, not peak. |
| System | Type | Replaces | Fits | Notes |
|---|---|---|---|---|
| EnDuraLast crank ignition (EDL-IGNS) | crank-triggered electronic | points / bean-can | pairs with EDL4 alternator | Purpose-designed to mount on the EDL4 PM alternator — the matched pair for a full front-of-engine modernisation. |
| Boyer Micro Digital / Micro-Power | digital timing + dwell | entire points/ATU system | '70–'80 (in-canister '79–'80) | Micro Digital keeps existing coils; Micro-Power uses Boyer's own — good dual-plug path. |
| Dyna III | electronic trigger | points | '70–'80 | Long-serving classic conversion. |
| Universal rule | coil Ω must match the ignition | — | every conversion | See Electrical §coils: wrong primary resistance kills modules or starves spark. Follow the ignition maker's coil spec, not what's on the bike. |
| Spec | Value | Applies | Notes | ||
|---|---|---|---|---|---|
| I/O | 12 inputs · 10 outputs | operating 9–15 V · −20 to +80 °C · ~180 g | any 12 V rewire | Outputs (+12 V): L & R signals, Lo, Hi, starter, horn, brake, ignition, AUX1, AUX2. Inputs: 1× +12 V switched (ignition lock or m.lock) + 11× ground-switched pilots incl. kill, kickstand, LIN-bus. Voltage window differs by generation: the current mo.unit blue/basic manual (V3.1) specifies 9–15 V, 12 V systems only, and warns that reverse polarity or anything above 15 V may damage the unit. The earlier m.unit blue/basic manual (V2.3) quoted 6–18 V. Neither generation is a 6–20 V device — check the manual revision that shipped with your serial number. | |
| Ground-switched logic | handlebar switches pull to GROUND | not +12 V | every input except LOCK | The single most important rewire concept. The one documented exception is the ignition lock input, which expects +12 V keyed, not ground — which is why the m.lock row below feeds it +12 V. Stock airhead switchgear and brake switches must be rewired to switch ground into the pilot inputs — a +12 V-switching brake pressure switch triggers nothing (a classic source of "dead brake light" mysteries on conversions). | |
| Switched capacity | headlight up to 200 W | starter solenoid up to 30 A | Lo/Hi · starter outputs | Integrated starter relay — the external Bosch relay goes in the bin. One-button Lo/Hi control supported. | |
| Digital fusing | 10 monitored circuits | no fuses on the OUTPUTS | all outputs | Fault = circuit shuts off + LED flashes at that output; fix the short, cycle the unit, function auto-restores. Diagnose on-device or in the mo.ride app. The outputs are self-fused; the supply is not — see the row below. | |
| Built-in functions | alarm · hazards · brake-light modulator | accel-triggered emergency flash · parking light | configurable | All configured via Bluetooth LE in mo.ride — flash patterns, signal timing, alarm sensitivity, keyless-go. | |
| m.lock pairing | RFID keyless ignition | feeds the +12 V switched input | your setup | m.lock replaces the ignition switch entirely; key fob or card wakes the system. Mount the antenna ring where the fob can get close through bodywork. | |
| Power feed & ground | 10 mm² (7 ga) battery cable, M5 terminal | one mount screw → battery negative | manufacturer requirement | install | The unit earths through its two M5 mounting screws, and motogadget requires that one of those screws be run directly to the battery minus terminal — not merely to a clean chassis point. Both the V2.3 and V3.1 manuals state this in the same words. Chassis metal alone is not the specified path: a powder-coated bracket is an open circuit, and even bare steel through an airhead frame gives you a resistance you did not design for. Motogadget's stated minimum supply cable is 6 mm²; 10 mm² is the comfortable choice. Main supply fuse 40 A maximum. |
| Airhead integration | 3 interfaces to plan | — | airhead rewires | (1) Ignition output feeds your electronic ignition/coils — verify the ignition's draw suits the circuit. (2) Stock Bosch charging still needs its GEN-lamp excitation path — the m.unit doesn't provide it; keep the lamp/330 Ω circuit, or a PM system (EDL4) sidesteps it entirely. (3) Brake inputs: both front hydraulic and rear switches wired as ground-triggers. |
| Terminal | Goes to | Wire | Side | Notes |
|---|---|---|---|---|
| + (battery feed) | battery positive via 40 A fuse | heavy red | power | The one fuse the unit cannot provide for itself. Motogadget cap it at 40 A; minimum 6 mm² cable. |
| GND (× 2) | chassis, and through the M5 mounting screws | black | power | Mounting surface must be clean bare metal — a powder-coated bracket is an open circuit. |
| LOCK | m.lock | brown · via 1 A fuse | input | The exception: +12 V keyed, not ground-switched. m.lock replaces the ignition switch outright. |
| START | Start/Stop button | red | input | Ground-switched, like every input below. |
| KILL | kill switch | violet | input | |
| TURN L / TURN R | left and right indicator switches | orange / blue | input | Both bar clusters share a common ground bar back to the unit. |
| HORN | horn button | magenta | input | |
| LIGHT | high-beam / light switch | dark blue | input | |
| BRAKE | front and rear brake switches, in parallel | green | input | Both must switch ground. A +12 V-switching pressure switch triggers nothing — the classic dead-brake-light fault on conversions. |
| STAND · LIN · AUX 1 · AUX 2 | side-stand switch · LIN bus · spare inputs | — | input | Config line runs on green in this loom. |
| IGNITION | ICU, and the coil +15 feed | — | output | Size this against your ignition's actual draw — see the integration row above. |
| START | starter solenoid | — | output | Integrated starter relay: the external Bosch relay comes out. |
| H BEAM / LIGHT | high beam · low beam + rear position light | dark blue / pale grey | output | The rear position lamp runs off the same LIGHT output as low beam in this loom. |
| BRAKE | rear brake light | green | output | |
| TURN L / TURN R | front left + rear left / front right + rear right | orange / blue | output | Two diodes near the headlight combine the running-light and indicator feeds. |
| HORN | horn | magenta | output | |
| AUX 1 / AUX 2 | registration plate lamp on one; spare | yellow | output | Number-plate light is the natural AUX load on an airhead rewire. |
| Item | Connects | Applies | Notes | |
|---|---|---|---|---|
| ICU (ignition control unit) | 6 pins → both coils | fed from IGNITION output | electronic ignition | Grounded at the unit. Switches the coil primary. |
| Ignition coils, L and R | wired in series — −1 to +15 | one plug each | as drawn | Two coils in series is the correct arrangement for points and for 1981–84 electronic — see the coil table above. Match the primary resistance to whatever is driving them. |
| Ignition transmitter unit | 3 wires → ICU | green · brown · blue | Hall sender | The bean can on the cam nose. Three pins; per-pin functions come from your year's factory schematic, not from wire colour alone. |
| Alternator | 3 phase wires → regulator/rectifier | yellow × 3 · plus D+ / D− | as drawn | Three phases into an external lithium-compatible reg/rec. Confirm your excitation path: a stock Bosch rotor still needs the GEN-lamp circuit that the m.unit does not provide, while a permanent-magnet system sidesteps it entirely — see the charging table in Electrical. |
| Lithium regulator / rectifier | alternator phases in, battery out | separately grounded | lithium battery | A lead-profile regulator is not interchangeable here. |
| CTEK charger port | battery via 20 A fuse | — | charging | Use a lithium-profile charger; desulfating lead chargers can damage a LiFePO4 BMS. |
| Motoscope Mini + combi frame | instrument feeds | — | cockpit | Takes speed from the GBX sensor, plus oil-pressure and neutral switches. |
| Oil pressure · neutral switches | → instrument | — | cockpit | Both are ground-switching senders on an airhead. |
| Spec | Value | Applies | Notes | |
|---|---|---|---|---|
| Form factor | Ø 12 × 25 mm · ~30 g | lives INSIDE the bar tube | m.unit blue / basic / v2 | Thimble-sized digital processor: all bar buttons connect to it locally, and ONE thin bus cable runs to the m.unit. The clip-on clean-look enabler. |
| Channels | L & R signal · Lo/Hi · starter · horn · front brake | — | bar-mounted controls | Button leads ~60 cm; bus cable to m.unit ~200 cm. |
| Button type | momentary, switching to ground | — | any pushbutton | Same ground-switched logic as the m.unit itself. Works with any momentary button — Motogadget's mo.switch (CNC billet, IP65, 22.2 mm & 1" bars, 2- or 3-button) is the matched hardware, but bar-end micro-buttons work too. m.unit handles the logic: press-again signal cancel, one-button Lo/Hi. |
| Spec | Value | Applies | Notes | |
|---|---|---|---|---|
| Sensor | Ø 30 × 14 mm · ~30 g · 8–18 V | 50 cm cable · 2× M3 rear mounts | hidden mounting | M3 screws max 2 Nm + medium Loctite. Battery-free NFC keys — fob, card, or tiny glass-tube transponder — each with a unique tamper-proof code; new keys "teach" to the lock. |
| Switching distance | ~40 mm through non-conductive material | glass tube: only 5–10 mm | mount planning | Hide it behind plastic, fiberglass, or leather — NEVER behind metal, which kills the field. On your build that rules out mounting under the steel seat pan or tank skin; a leather seat hump, fiberglass cowl, or side-cover zone works. Keep it ≥30 cm from ignition coils and HT leads. |
| Switching output | with m.unit: feeds the +12 V switched input | standalone: supplied 12 V/40 A relay | both install modes | Paired with an m.unit the relay is redundant — the m.unit IS the power switch. Standalone installs use the included automotive relay (up to 40 A rated switching). |
| Battery protection | 3-stage quiescent-current reduction | status LED | NFC version | Steps its own standby draw down when parked — kind to a small LiFePO4. |
| Hard-crank caveat | voltage sag can release the relay | backup capacitor #4002002 | standalone relay installs | High-compression engines + certain batteries sag enough during cranking to drop the relay mid-start. The capacitor holds the relay coil through the sag. m.unit-paired installs are inherently less exposed. |
| Product | Spec | Key numbers | Fit | Notes |
|---|---|---|---|---|
| motoscope tiny / tiny speedster | Ø 49 mm analog speedo, 24 mm deep | ~96 g · ~200 mA · warning LEDs: signal, hi-beam, neutral, hazard | café cockpits | Stepper-motor needle, digitally driven. Speedster variant is all-analog with a 40s/50s streamline dial — the natural pick for your cream/copper aesthetic. Comes with M5 stainless wheel sensor (IP68) + neodymium magnets, 150 cm cable, teach-function calibration. Going electronic sidesteps the W-ratio speedo/final-drive pairing problem entirely (see Trans §ratios) — swap rear-drive ratios freely, re-teach, done. |
| motoscope mini / pro | LED-display instruments | — | minimalist / full-data builds | Mini is the flush LED strip readout; Pro is the full multi-function unit. Both can take OEM reed/proximity sensor inputs. |
| mo.blaze disc | bar-end signal, TranzLight disc | Ø 35 · 68 mm total · 48 mm inside bar · ~7 W | 7/8" & 1" bars, 14–21 mm ID | The transparent disc IS the light — invisible until lit, then fiercely bright fore and aft. US legal note: not DOT approved, sold "show use only" — worth knowing before NJ inspection. Blaze pin is the tiny conventional-mount alternative for the tail. |
| mo.view glassless mirrors | machined aluminum IS the mirror | diamond-flycut convex face, plasma-coated | bar-end, many shapes | No glass to shatter, no frame, shake-free at speed. Café / spy / blade / flight shapes; ball-joint adjust; mountable above or below the bar. |
| Bar real-estate budget | disc: 48 mm in-bar · adapter: 90 mm free tube · m.button inside bar too | — | clip-on planning | The uni disc/cone adapter stacks a mo.view mirror AND a blaze disc in one bar end — but everything (signal body, adapter, m.button, internal wires) competes for the same tube. On clip-ons, map the internal lengths per side before ordering. |
| LED flashing logic | m.unit: load-independent, built in | standalone: m.flash / m.wave relay or resistors | all LED signals | With an m.unit, no load resistors and no flasher relay — flash rate is configured in mo.ride. Only standalone (non-m.unit) installs need the relay. |
| Upgrade | What it does | Applies | Notes | |
|---|---|---|---|---|
| LiFePO4 battery | light, high CCA, slow self-discharge | needs BMS + correct charge voltage | upgraded charging only | Verify regulator setpoint suits lithium (EDL4Li or modern reg/rect). Old mechanical VRs and lithium don't mix. Size honestly — airhead starters pull hard (your NLP30 upsize was the right call). |
| LED dash / GEN lamp caveat | LED bulb may not excite rotor | stock Bosch systems only | stock charging + LED dash | The GEN lamp's current excites the rotor — an LED passes too little. Fit the 330 Ω 1–2 W parallel resistor (Electrical §charging) or run a PM system, which doesn't care. |
| Battery | Type | Key numbers | Fit | Notes |
|---|---|---|---|---|
| Panasonic LC-X1228P | AGM · 28 Ah | same posts as OEM | true drop-in | The "looks stock, works better" choice — OEM 28 Ah format, no brackets or rigging. |
| Odyssey PC680 (ODS-AGM16L) | pure-lead AGM | 170 CCA · 400 cycles @ 80% DoD | half-fills the tray — shim it | The airhead cult favourite: vibration-proof, 4–6 h recharge, −40 to +140 °F, 10+ year service reports. Bigger sibling PC925 fills an RT-size tray (spacers still wise). |
| MotoBatt MBTX30HD | AGM · 30 Ah class | highest CCA in class | fits WITHOUT subframe removal | Slides in past the airbox — no rear-frame surgery. Strong storage tolerance. |
| Deka ETX20L | AGM | — | common fit | Widely used; same charging caveat as all AGMs below. |
| LiFePO4 (NOCO NLP30, Antigravity…) | lithium iron phosphate | huge CCA-to-weight, tiny self-discharge | upgraded charging only | Your NLP30 path. Size for airhead starter draw — an undersized lithium clicks and cranks slow (as you found firsthand). Cold mornings: pulse the starter or lights briefly to wake the cells before cranking. Charge only with lithium-profile chargers; desulfating lead chargers can damage the BMS. |
| The AGM undercharge trap | AGMs want 14.6–14.8 V at the battery | stock system delivers ≤14 V at best | every stock-charging airhead | The Bosch RE55/RE57 setpoint (14.2 V) minus loom losses = chronic 90%-charged AGMs, hopeless in city traffic with the headlight on. Fixes: adjustable regulator (EME VR-EXTADJ) set with a meter AT the battery posts, clean every charging connection, or go PM (EDL4/4Li) and set it right once. This — not bad batteries — is why airheads "eat" AGMs. |
| Check | Limit | Applies | Notes | ||
|---|---|---|---|---|---|
| Rim run-out — spoked | radial 0.5 mm / lateral 0.3 mm | .020" / .012" | twin-shock · 36-0/3 | BMW-RA382 Measured at the rim flange, tyre off. The .020" figure that circulates as a universal limit is the spoked-wheel radial number only — the lateral limit is tighter. | |
| Rim run-out — cast alloy | 0.3 mm both directions | .012" | buy/keep standard | cast wheels | BMW-RA382 0.3 both ways — and the 12.77 RS column agrees. BMW-WSM7 §36 But the ’79 and 1981 sheets print a looser 0.9 radial / 0.5 lateral at the rim shoulder as the service figure. Conflict recorded: use 0.3 when judging a wheel to keep, the sheet figure only when deciding whether one is unserviceable. |
| Position | Stock | Upsize ladder | Rim | Notes |
|---|---|---|---|---|
| Front — twin-shock | 3.25H-19 | 90/90-19 → 100/90-19 fits fine | 1.85 × 19 | 3.50 also usable. Handling changes slightly off stock size. |
| Rear — twin-shock | 4.00H-18 | 110/90-18 fits most · 120/90-18 = maybe | 2.15 × 18 (std) · 2.75 × 18 (RS/RT) | The honest ceiling: 110/90-18 is the safe universal upsize. 120/90-18 works best on the wider 2.75" RS/RT rim; on a 2.15" rim it distorts the profile and may rub the swingarm. BMW's own fix: 10.7 mm wheel spacer 36-31-2-301-737 (stock 9.2 mm) — sometimes needed with a 120 even on '81+ twin-shocks. |
| The rub-at-speed trap | tires grow in WIDTH with speed | garage clearance ≠ road clearance | every oversize | A rear that clears on the stand can rub the swingarm at highway speed — you'll usually smell it first. Blocky enduro treads interfere worst, even in stock sizes. Mount, inflate, measure, then road-test progressively. |
| Sizing truth | rim width sets max tire | not the sidewall number | all builds | A wide tire pinched onto a narrow rim gets a taller, squirmier profile — worse handling, not more grip. No true metric equivalent exists for 3.25-19 / 4.00-18; inch sizes remain available (Michelin Road Classic, Conti RB2/K112, Shinko 270). |
| Element | The play | Key numbers | Applies | Notes |
|---|---|---|---|---|
| Conversion architecture | custom stem + billet trees + taper bearings | Cognito Moto makes airhead-specific stems | any modern fork → airhead frame | The kit formula: frame-specific stem pressed into donor-fork triple clamps, All Balls taper-roller conversion bearings + seals for the airhead steering head, adjustable steering stops (so the new forks never kiss your tank). Bearing preload torques to the DONOR fork's factory spec, dual locknuts always. |
| Offset = the geometry decision | fixed offsets: 30 / 45 / 50 / 55 / 60 mm | 45–60 mm for 18–19" wheels · 30 mm for 17" | every swap | Sportbike trees have short offsets designed for 17" wheels — bolt them on unchanged with your 19" front and trail goes wrong. The whole point of conversion trees is choosing offset to land near-stock trail with YOUR wheel size. This is the difference between a swap that looks fast and one that steers right. |
| Donor fork menu | GSX-R · CBR · R6/R1 · Hayabusa · ZX-series | — | cartridge or big-piston USD | GSX-R is the default: cheap donors, huge parts supply, modern damping + radial brake mounts in one move. Donor forks are typically shorter than airhead forks — front drops, rake steepens, steering quickens. Tune ride height by sliding tubes in the clamps; account for it in stance planning. |
| R nineT front end | the BMW-family path | 30/30 mm stem · 45 mm offset w/ wheel adapter | airheads via Cognito R9T kit | Modern BMW USD forks + Cognito's R9T-wheel-to-airhead adapter — keeps it Bavarian. Their own recommendation: 45 mm offset with that wheel combo. |
| Wheel & brake strategy | hub bolt-on kits keep the spoked look | GSX-R / R6 / CBR axle standards | heritage builds | Hub conversion kits mount spoked wheels on modern axles — vintage face, radial calipers behind it. Budget the master cylinder to match the new calipers' piston volume; the vintage master won't push modern 4-pots correctly. |
| Cockpit integration | Motoscope Pro top clamp | gauge machined into the tree at viewing angle | Cognito competition series | Cognito machines a top clamp with the Motogadget Motoscope Pro recessed in — trees, gauge, and risers as one designed unit (see Motogadget §cockpit). |
| The period-correct alternative | K75/K100 conventional forks | BMW-to-BMW, ~bolt-friendly | budget / subtle builds | The classic quiet upgrade: stouter later-BMW conventional forks with a period profile — pro builders have used K75 front ends on R100 customs for decades. No USD look — but do not read that as no geometry work. A BMW-to-BMW swap still changes fork length, triple-clamp offset and therefore trail; you must confirm fork length and offset, wheel/axle and brake fitment, and that the steering stops still limit lock before the tank or the lines are loaded. It is a well-trodden swap, not a bolt-on. |
| Upgrade | Benefit | Applies | Notes | |
|---|---|---|---|---|
| Dual-plug heads | detonation margin, mileage | machined 2nd plug per head | esp. 8.2:1 US engines | Needs dual-output coils (Accel 140404 pair or Boyer Micro-Power) and retimed ignition. Popular pairing with the lean-jet era. |
| Deep oil pan | +~1 L capacity, cooler oil | — | hot climates / hard use | Keep level under full mark to increase case air volume and reduce breather misting. |
| Progressive fork springs | better front control | ~1" preload starting point | all airhead forks | Try ~5 cc less oil than book when experimenting; never raise viscosity to mask stiction. |
| '85-style rocker shim kit | shimmed end play, quieter valves | kit 11-33-9-057-699 | '76–'84 heads | Plus support bushings 11-12-1-261-405. See Valve Gear §rockers. |
| Output-shaft circlip retrofit | stops bearing drift | groove + clip at rebuild | later 5-speeds | See Transmission §known issues — cheap insurance whenever the box is open. |
| Carb hose update | 13-72-1-254-654 | replaces -360 | late R100 | See Carburetion §service — fixes vibration-induced rich running and needle wear. |
| Kit | What it is | Key numbers | Fits | Notes |
|---|---|---|---|---|
| Replacement Kit 1000cc | new Nikasil cylinders + pistons | 9.5:1 pistons, ~110 g lighter than stock · SS pushrod tubes pre-installed | all 1000cc airheads (TÜV-approved) | THE fix for the 1981-on no-rebore dead end, and gives '77–'80 iron-liner bikes the Nikasil benefits BMW introduced in '81: near-zero bore wear, better heat dissipation, improved oil control. |
| Power Kit 1000cc | 750/800/900 → 1000cc conversion | stepped 9.5:1 pistons | R75 / R90 / R80 | The stepped piston clears the smaller combustion chamber but compromises the squish band — part of why dual-plugging is recommended. The refined path: machine the heads to R100 squish geometry (skrunkwerks-style) for true 9.5–10:1 without the detonation tendency. |
| Big Bore Kit 1070cc | 1000 → 1070cc | — | post-'81 R100s (your engine's path) | The "more muscle" option for exactly your generation of engine. |
| Power Kit 860cc | R45/R65 upsize | +~40% power, torque from ~2200 rpm | R45 · R65 · R65GS · R65LS · Monolever | Forged pistons in coated liners. Four kits split by pre-/post-9/80 construction and by output version (27 hp vs 48 hp) — see the part numbers in Parts & Fiche. |
| Compression management | 9.5:1 kits on 8.2:1-era bikes | low-comp base gaskets → 8.8:1 | every kit install | Options: premium fuel + richer jetting (see Carburetion), dual-plug heads, or the low-compression base gaskets (e.g. 11-11-1-335-650) for single-plug pump-gas peace. Higher compression + the lean '81 US jetting = ping city if ignored. |
| Install & integration notes | 3 gotchas | — | planning | (1) Kits split at the autumn-1980 crankcase redesign (different case cut-out) — order by build date. (2) Kit circlips are internal locking rings, fiddlier than the original external clips. (3) An R80→1000 conversion keeps the short R80 final drive — buzzy 5000 rpm cruising until you swap to an R100 ratio (see Trans §ratio ladder). |
| Stainless braided brake lines | firmer lever, no hose swell | — | all hydraulic brakes | Biggest single feel improvement on vintage ATE/Brembo systems. Torque banjos gently — see Torque §34 (6–7 ft-lb). |
| Quality rear shocks | Ikon (Koni lineage) · Hagon · YSS | — | twin-shock | Stock units are usually decades past done. Match spring rate to café weight loss — stock rates over-spring a stripped bike. |
| Fork brace | stiffens the long stanchions | — | /5–/7 forks | Assemble carefully aligned — a misaligned brace ADDS stiction (see Capacities §fluid rules). |
| Vendor | Specialty | Reach for them when… | Where | Notes |
|---|---|---|---|---|
| Corner Custom | build videos | airhead cafés & scramblers | YouTube & Instagram | Sijard's own channel — the work in the Build Gallery, filmed. Useful for seeing how a USD conversion, a rewire and a blacked-out engine actually go together rather than only how they finish. youtube.com/@corner.custom |
| Cognito Moto | front-end conversions | USD swap, conversion stems, hub kits, triple trees | Oilville, VA — made in USA | Airhead-specific stems, fixed-offset trees, spoked-hub kits for modern axles, Motoscope-integrated top clamps. Lifetime warranty. Will custom-make stems from your clamps if they lack data. |
| Siebenrock | engine kits | cylinders, big-bore, replacement Nikasil | Germany | See dedicated §Siebenrock group above. TÜV-approved kits. |
| EuroMotoElectrics (EME) | charging & ignition | EnDuraLast systems, adjustable regulators, coils, starters | Denver, CO | The EnDuraLast source; also the VR-EXTADJ adjustable regulator for the AGM undercharge fix, plus a deep stock of Bosch/Valeo electrics. |
| Motorrad Elektrik | electrical specialist | Omega charging systems, coils, harnesses | USA | The other veteran airhead-electrics house — Omega alternator systems (Snowbum-tested alongside EnDuraLast), quality coils, Odyssey batteries. |
| Motogadget | control electronics & cockpit | m.unit ecosystem, gauges, signals, mirrors | Berlin — via Revival, Analog, Dime City, Lossa | See dedicated groups above. |
| Cycle Works | transmission tooling | shim kits, measuring plates, NLA shims | USA | The source for gearbox shimming — sells the measuring plate the factory method needs and shims BMW discontinued. |
| Ted Porter's BeemerShop | engine machine work + Siebenrock | valve jobs, head overhaul, kit supply | Scotts Valley, CA | Siebenrock dealer with the head-work expertise to install them right; source of the low-compression base gasket guidance. |
| skrunkwerks | head machining & analysis | squish-band correction for Power Kits, porting | AU | The squish-geometry specialists — machine R75/80/90 heads to R100 spec for detonation-free 9.5–10:1 on Siebenrock pistons. Also authored the definitive AGM-undercharge analysis. |
| Rubber Chicken Racing Garage | rebuild services | Tom Cutter — engines, Nikasil replating coordination | PA | One of the most-referenced pro airhead wrenches; the replate-and-hone-to-piston path for worn Nikasil cylinders. |
| Long's Mechanical Services | cylinder head rebuilding | valves, guides, seats, dual-plug machining | PA | The head-rebuild reference (Randy Long) — dual-plug conversions done properly. Also close to you. |
| Omega Racer | custom bodywork | hand-formed alloy tanks, seat cowls, full exhausts | specialist, R100-focused | Handcrafted aluminum for R100 café builds — tanks, fairings, cowls, slip-ons and full systems. |
| Boxer2Valve | parts & literature | jets, consumables, factory parts catalogs | USA | Deep airhead consumables stock plus the licensed reprint factory parts catalogs — the exploded-diagram bibles. |
| MAX BMW | OEM parts | online fiche + genuine BMW stock | Northeast US | The go-to OEM fiche with live part numbers; pair with RealOEM for build-date verification. |
| Bench Mark Works | vintage /2 & earlier | pre-airhead parts & knowledge | USA | When the project predates 1970 — carb spec sheets, /2 restoration stock. |
| Revival Cycles | builder-dealer | Motogadget + EnDuraLast + build consulting | Austin, TX | Pro builders who sell what they install — known for patient Motogadget rewire support on airhead resto-mods specifically. |