Aprilia RS 660 upgrades
The RS 660 landed with RSV4-grade electronics, a MotoAmerica Twins Cup grid waiting for it, and a race-parts ecosystem that showed up within a season. It's the modern answer to 'one middleweight for street and track' — and almost nobody's stays stock past the first month.
Spec plate & generations
Claimed figures and the generation map. The year splits decide whether a part fits.
- Engine659 cc 270° parallel twin
- Power~100 hp claimed (2021–24); ~105 hp 2025+
- Wet weight~403 lb claimed
- Seat height32.3 in
- ElectronicsAPRC suite, 6-axis IMU, bidirectional quickshifter standard
Generation map
- RS 6602021–2024
Launch generation: ~100 hp claimed 270° twin, full APRC electronics with bidirectional quickshifter standard, KYB fork/Sachs shock, Brembo radial calipers. Early 2021 builds fall under the con-rod recall (NHTSA 21V-502) — affected engines were replaced whole; verify by VIN.
- Extrema2023
Limited edition: SC-Project silencer, carbon bits, solo-seat tail. Chassis and most parts fitment track the standard 2021–24 catalog.
- 2025 refresh2025–present
~105 hp claimed via 52 mm throttle bodies, new fairing with integrated winglets, launch control added; new Factory trim ships Öhlins NIX30 fork and STX46 shock. Bodywork and screens from 2021–24 do not fit.
Street path & track path
Two ordered sequences for the same machine. The order is the advice: spend where the next problem is, not where the catalog is loudest.
Street path
Clean the tail
Fender eliminator and flush signals — the stock plate hanger is the first thing every owner deletes. Bar-end mirrors are a common follow-up; the stock mirrors are a running complaint.
Protection
Frame sliders and engine case covers. Twins Cup supply means good coverage: GB Racing and Woodcraft both list the 660, and US race vendors like Spears Racing stock 660-specific protection.
Slip-on
The SC-Project CR-T is the signature RS 660 pipe (it's what the Extrema wears); Akrapovič and LeoVince cover the other price points. Slip-ons keep the mid-pipe cat, so they run fine without a tune.
Levers and grips
Shorty adjustable levers (ASV, CRG) and tank grips. Cheap no-name levers are a recurring gamble in 660 owner threads — buy once.
Tune when the cat goes
A full decat system without a tune means a check-engine light. If you're going full system, budget the flash with it — that pairing is where the twin's midrange fills in (community consensus, not a dyno promise).
Spring for your weight
Base KYB/Sachs suspension is budget-grade and sprung for a light rider. Springs matched to your weight transform it; full cartridges can wait for track duty.
Track path
Tires
Supercorsa SP or Q5 on the stock 120/70-17 and 180/55-17 sizes. The chassis is honest enough that rubber is the whole first step.
Brake consumables
Race pads, braided lines, fresh fluid, lever guard. The stock Brembo radials are good hardware — feed them better pads before touching anything else.
Suspension
Cartridge kit and shock, sprung for your weight — Öhlins and K-Tech both catalog the 660, and Twins Cup teams have published baseline setups. 2025 Factory bikes arrive with Öhlins already.
Ergonomics
Rearsets (Bonamici and Woodcraft are the Twins Cup picks) and adjustable clip-ons. Budget eBay rearsets on this bike are a documented community gamble.
Make it crash-able
Case covers, axle sliders, race bodywork. 660 race fairings are widely available thanks to Twins Cup — but 2025+ winglet bodywork is its own fitment.
Full system, tune, gearing
Full exhaust with a matched flash, then gear it per track — stock gearing is tall for tight circuits and a rear sprocket change is the cheap fix.
Parts notes for the RS660
What fits and what the community runs, category by category. Typical street prices sit at the other end of the links.
Exhaust
SC-Project CR-T is the signature look; Akrapovič, Arrow and LeoVince cover the ladder. Read listings carefully — the cat lives in the mid-pipe, so 'slip-on' vs 'full decat' changes both sound and whether you need a tune. Full systems without a flash throw a CEL.
Some links may earn Unstocked a commission at no cost to you. Prices shown are typical street prices — always verify fitment and price at the retailer. Model-specific parts (exhausts, rearsets, bodywork) can run 2–3× between platforms — the sheet shows a typical figure.
Tune
Mail-in flash culture is thinner for Aprilia than for Japanese brands. The paths: a 660-experienced US tuner, or Aprilia's race ECU route for dedicated track bikes. Twins Cup teams (Robem Engineering among them) developed most of the race maps in circulation.
Some links may earn Unstocked a commission at no cost to you. Prices shown are typical street prices — always verify fitment and price at the retailer. Model-specific parts (exhausts, rearsets, bodywork) can run 2–3× between platforms — the sheet shows a typical figure.
Suspension
Base bikes run budget KYB fork/Sachs shock — spring for your weight first, then K-Tech or Öhlins cartridges and shock for track pace. The 2025 Factory ships Öhlins NIX30/STX46 from the crate.
Some links may earn Unstocked a commission at no cost to you. Prices shown are typical street prices — always verify fitment and price at the retailer. Model-specific parts (exhausts, rearsets, bodywork) can run 2–3× between platforms — the sheet shows a typical figure.
Brakes
Stock Brembo radial calipers on 320 mm discs are better than the price class suggests — pads, braided lines and fluid are the whole upgrade for most riders.
Some links may earn Unstocked a commission at no cost to you. Prices shown are typical street prices — always verify fitment and price at the retailer. Model-specific parts (exhausts, rearsets, bodywork) can run 2–3× between platforms — the sheet shows a typical figure.
Rearsets
Bonamici and Woodcraft dominate the 660 paddock; Gilles is the street-premium option. Community threads on cheap eBay/Arashi rearsets for this bike are mixed at best.
Some links may earn Unstocked a commission at no cost to you. Prices shown are typical street prices — always verify fitment and price at the retailer. Model-specific parts (exhausts, rearsets, bodywork) can run 2–3× between platforms — the sheet shows a typical figure.
Crash Protection
Case covers are mandatory at most track orgs — GB Racing and Woodcraft list the 660. Spears Racing and other Twins Cup vendors carry model-specific sliders, guards and spools.
Some links may earn Unstocked a commission at no cost to you. Prices shown are typical street prices — always verify fitment and price at the retailer. Model-specific parts (exhausts, rearsets, bodywork) can run 2–3× between platforms — the sheet shows a typical figure.
Bodywork
Double-bubble screens (Zero Gravity, Puig) are a common comfort fix for taller riders — but 2025+ winglet fairings take different screens than 2021–24.
Some links may earn Unstocked a commission at no cost to you. Prices shown are typical street prices — always verify fitment and price at the retailer. Model-specific parts (exhausts, rearsets, bodywork) can run 2–3× between platforms — the sheet shows a typical figure.
Drivetrain
Stock gearing is long for track work; a 1–2 tooth rear sprocket bump is the cheap, reversible fix. Twins Cup bikes regear per circuit — 520 conversion kits (Vortex/EK, Driven) are catalogued for the 660.
Some links may earn Unstocked a commission at no cost to you. Prices shown are typical street prices — always verify fitment and price at the retailer. Model-specific parts (exhausts, rearsets, bodywork) can run 2–3× between platforms — the sheet shows a typical figure.
Electronics
APRC already covers TC, wheelie control, engine maps and the up/down quickshifter. The meaningful add-on is data: an AiM Solo 2 DL reads the bike's ECU channels.
Some links may earn Unstocked a commission at no cost to you. Prices shown are typical street prices — always verify fitment and price at the retailer. Model-specific parts (exhausts, rearsets, bodywork) can run 2–3× between platforms — the sheet shows a typical figure.
Gotchas & fitment traps
The year splits and part quirks that eat money on this platform.
Cross-model interchange
Community-reported. Paddock folk knowledge, not manufacturer fitment data. Verify part numbers for your exact year and market before spending.
- Tuono 660 shares the engine and frame — community-reported crossover on engine covers, protection hardware, drivetrain and many engine-adjacent parts; bodywork, subframe/tail and cockpit (clip-ons vs handlebar) do not swap.
- Tuareg 660 and the 660 adventure family use the same engine platform in a different state of tune — community consensus is that accessory and performance parts generally do not cross. Verify per part.
Aprilia RS 660 FAQ
Is the Aprilia RS 660 good for track days?
It's one of the default middleweight track bikes of the 2020s — light, electronics-rich, and raced in MotoAmerica Twins Cup, so race parts and setup knowledge are everywhere. Tires, brake pads and springs for your weight make it a genuinely quick track package.
Does an RS 660 slip-on need a tune?
A true slip-on that keeps the mid-pipe cat runs fine stock. A full system or decat throws a check-engine light and wants a flash — plan them as one purchase.
What recalls affect the RS 660?
The big one is the 2021 connecting-rod recall (NHTSA 21V-502) covering early builds — Aprilia swapped complete engines. Any 2021 bike should show the recall closed on a VIN check.
Do RS 660 and Tuono 660 share parts?
Engine, frame and most protection/drivetrain parts, yes (community-reported). Bodywork, tail sections and cockpit controls differ — the Tuono runs a handlebar where the RS runs clip-ons. Check each listing's fitment line.
What changed on the 2025 RS 660?
About 5 more claimed hp from 52 mm throttle bodies, a new winglet-integrated fairing, launch control, and a new Factory trim with Öhlins suspension. The visual refresh also means 2021–24 bodywork and screens don't carry over.
Read before you spend
Chapters from the manual that apply to the RS660.
Builds on the RS660
Reference sheets assembled by the shop — every part at typical street prices. Open one and steal the order.
Prices are typical US street prices at publish time and drift with sales and supply — verify at the retailer. Fitment is advisory: always confirm the exact part number for your year, generation and market before buying.