This is a resources page for the Ducati Monster 821 made between 2015 and 2020. It’s powered by the 821 cc liquid-cooled 8-valve “Testastretta 11” engine.
The Ducati Monster 821 is an interesting bike in Ducati’s line-up. It represents the first time that the “small” Ducati Monster — smaller than its contemporary big sibling, the Ducati Monster 1200 — cleared 100 hp with a willing, sporty engine.
But the Monster 821 is sadly overshadowed on four sides, by the 1200 on one, by the newer (and more powerful, higher-tech, and lighter 937) on another, by nostalgia for air/oil-cooled big Monsters on a third, and by every other middleweight naked sport bike on the fourth.
This all just means that many of us forget how wonderful the Ducati Monster 821 is. If you’re thinking about it, you’re probably wondering:
- How does the Ducati Monster 821 fit within the Ducati line-up?
- Stripe, Stealth, Dark, Cromo — What are all the differences?
- Maintenance — What’s it like?
- How did the Monster 821 evolve?
- What are some alternatives to the Monster 821?
I’ll provide all this information here — and more. Let’s go!
You might also like the broader Ducati Monster buyer’s guide.
I compile information like this on motorcycles to help current and prospective motorcycle owners (including myself!). Below you can find information on the maintenance schedule and service intervals, as well as parts you need for a standard service, guidelines for basic services like oil changes, drivetrain maintenance, and torque specs.
Note: Motofomo is reader-supported. If you buy some of the products that we link to, we may earn an affiliate commission, which otherwise goes to the marketplace (e.g. Amazon).
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About the Ducati Monster 821
Ducati unveiled the Ducati Monster 821 for the 2015 model year as a successor to the earlier Ducati Monster 796. The 821 is a huge update, with a much more advanced engine that makes more power, is more responsive, and has much wider service intervals.
At its heart, the Ducati Monster 821 maintains its original charm — a middleweight naked sport bike that strikes a balance between the fierce Streetfighter range and the casual fun Ducati Scrambler range (which came a bit later, but which shares an engine with the 821’s predecessor).
The Monster 821 is an everyday bike that is spirited, yet manageable to ride. It’s stripped-back, with very few frills, and a midrange-focused engine that doesn’t need you to wind it out to get the most out of it.
The big change for the Monster 821 is the motor. Ducati ditched the Desmodue for a 4-valve-per-cylinder liquid-cooled block that makes much more power than before, despite having only a slight bump in capacity.
Under the hood, the Monster 821 shares its 821 Testastretta-11 engine with the Ducati Hypermotard 821 — an 821-cc liquid-cooled 8-valve 90-degree V-twin, forward canted, called an L twin. The “Testastretta 11” moniker is shared with its contemporary, the Monster 1200, as well as other motorcycles of the generation.
Here’s how the motors stack up.
|Part||Monster 796||Monster 821 (Later spec)||Monster 1200 (base)|
|Engine designation||Desmodue L-twin||Testastretta 11-degree L-twin||Testastretta 11-degree L-twin|
|Capacity||803 cc||821 cc||1198 cc|
|Bore / Stroke||88 x 66 mm||88 x 67.5 mm||106 x 67.9 cc|
|Timing system||Belt-driven camshafts||Belt-driven camshafts||Belt-driven camshafts|
|Valves per cylinder||2||4||4|
|Peak power||64 kW / 87 hp @ 8250 rpm||80 kW / 109 hp @ 9250 rpm||110 kW / 150 hp @ 9250 rpm|
|Peak torque||78 Nm / 56 lb-ft @ 6250 rpm||86 Nm / 63 lb-ft @ 7750 rpm||126 Nm / 93 lb-ft @ 7750 rpm|
|Oil change service interval||7500 mile / 12000 km||9000 mile / 15000 km||9000 mile / 15000 km|
|Valve inspection service interval||7500 mile / 12000 km|
|18000 mile / 30000 km||18000 mile / 30000 km|
The Testastretta 11-degree engine is the road-going variant of the Testastretta motor used in the Ducati superbikes. It shares a design and many characteristics. But Ducati reduced the valve overlap (to 11 degrees, surprise!) to improve low-rpm performance, even though that comes at a cost to top-end rush — a reasonable compromise for bikes not designed exclusively for the track.
See here for a guide to Ducati motorcycle engines, from Desmodue onwards, including of the Testastretta variants.
In its base configuration, the Ducati Monster 821 is kitted with a KYB 43-mm upside down fork and a Sachs monoshock offering rebound and spring preload adjustability. The Monster 821 is also available in various other trims (e.g. Stripe, Stealth) with fully adjustable front suspension. (See the below section on model variants.)
The braking system consists of dual 320mm discs with Brembo M4.32 calipers — a common setup for premium street bikes.
One significant advantage of the liquid-cooled engine in the Ducati Monster 821 is its extended service intervals. It needs oil changes every 15000 km / 9000 miles, but valve services are required only every 30000 km / 18000 miles. This is a similar width to other contemporary middleweight sport motorcycles.
Despite the extended intervals, servicing the valves on a Ducati is no picnic. The motor in teh Monster 821 is still a Desmo motor (see here for an explainer), which means the eight valves have openers and closers — so there’s a total of sixteen clearances to check. Plus, you have to check both the forward and rear cylinder, and at the same time change the timing belts.
At least the Ducati Monster 821 has five-year belt replacement intervals, a significant improvement over earlier models which needed replacement every two years.
In 2018, Ducati gave the Monster 821 a minor makeover with a new tank, tail section, headlight, and muffler, aiming for a more “classic” aesthetic akin to the original Monster 900. Despite these tweaks, the engine and basic maintenance remained unchanged.
In 2021, the Ducati Monster was replaced by the new Ducati Monster and Monster+, colloquially referred to as the Ducati Monster 937.
Ducati Monster 821 Specifications
Here are the core specifications for the Monster 821, along with some notes. See the section further below for variants of the Ducati Monster 821 line.
|Engine type||Testastretta 11-degree, Liquid-cooled L-twin, Desmodromic 4-valve per cylinder||Similar layout to the contemporary 1200|
|Bore x stroke (mm)||88 mm / 67.5 mm||1.75 mm longer stroke than the 796 (803 cc)|
|Peak power||81 kW / 112 hp @ 9250 rpm|
(80 kW / 109 hp for Euro 5 version)
|Peak torque||89 Nm / 66 lb-ft @ 7750 rpm|
(86 Nm / 64 lb-ft Euro 5 version)
|Transmission||6- speed, chain drive|
|Front suspension||Inverted 43mm fork. Spec Varies — See below|
|Rear suspension||Sachs rear shock, preload / rebound adjustable|
|Front brakes||2 x 320 mm discs, Brembo M4.32 calipers (Radially mounted / Monoblock)|
|Wet weight||~205 kg / 453 lb (Curb weight)|
|Ride aids||Ride modes, Power modes, ABS, Traction control|
Monster 821 Generations / Model Variants
The Ducati Monster 821 came in two distinct generations: 2015-2017 and 2018-2020. The later model dropped a few peak horsepower due to emissions constraints, but it’s not noticeable.
|Item||2015-2017 Monster 821||2018-2020 Monster 821|
|Peak power, base trim||112 hp @ 9250 rpm||109 hp @ 9250 rpm|
|Quick shifter||No||Optional (Standard on Stealth)|
|Colours||Red, Black, Grey||Red, Yellow, Dark Stealth (for Stealth version)|
|Special versions||Dark, Stripe||Dark, Stealth|
If you’re not sure which one you’re looking at, look for the TFT display!
The Ducati Monster 821 also came in a higher-spec “Stripe” and “Stealth” spec in various years with a fully adjustable fork. The Stealth also came with a standard up/down quick shifter.
|Model||Monster 821 (base model) / Dark||Monster 821 Stripe (2015-2017)||Monster 821 Stealth (2018-2020)|
|Front suspension||43mm Kayaba USD fork, non-adjustable||43mm Kayaba USD fork, fully adjustable||43mm Kayaba USD fork, fully adjustable|
|Rear suspension||Sachs rear shock, preload / rebound adjustable||Sachs rear shock, preload / rebound adjustable||Sachs rear shock, preload / rebound adjustable|
|Quick shifter||Optional (2018-2020)||No||Standard|
|Fly screen||Optional||Standard (“Nose fairing”)||Standard|
Using the Ducati Monster 821’s Screen and Controls
When assessing any motorcycle, I like to have an overview of the interface and the important controls — things like cruise control, rider aids, and adjusting rider settings.
Both generations of the Ducati Monster 821 had the following settings customisable:
|Riding modes||Sport, Touring, Urban. All settings are customisable. Pre-set DTC in each ride mode, though it can be customised.|
|Power modes:||Low (low power, “smooth” power delivery)|
Medium (full power, “smooth” power delivery)
High (full power, “instant” power delivery)
|Traction control (DTC)||Eight (8) levels.|
– Level 1 is for expert riders, with rare intervention, on a track.
– Levels 1-3 allow for skidding of rear wheel around a corner
– Levels 4-5 for a fast touring style
– Level 6 for urban
– Level 7-8 recommended for wet roads
– Level 8 is most aggressive, intervening with even slight slipping
|ABS||Three levels of intervention. Also, it can be disabled.|
– Level 1: Controls both wheels, but with no anti-lift. Maximum braking power.
– Level 2: Controls both wheels, with anti-lift. Focuses on braking power with good stability.
– Level 3: Both wheels, with anti-lift. Focuses on maximum stability.
The riding modes are configured as standard as:
|Riding mode||Default Power level||Default ABS level||Default TC level|
|Touring||Med (“smooth” power curve)||2||4|
|Urban||Low (“smooth” power curve)||3||6|
To change ride mode on the Ducati Monster 821, you press on the middle of the turn signal button, also known as the “confirm” button.
Press the button repeatedly until you get the right ride mode, and then confirm by holding down the button for two seconds. Note: If you don’t confirm the ride mode by pressing the button for two seconds, and just leave it, then the bike will go back to the mode it was already in!
You can do this while riding, but you have to be not pressing brakes or have the throttle open. If you do change the ride mode while riding, the motorcycle will wait until you let go of the brake or throttle to change the ride mode.
You can also customise the riding mode by holding down the confirm button (the turn signal cancel button) for two seconds while the bike is stationary, and using the toggle buttons to move between the menu items and making changes.
Changing screen mode
On the 2018+ model with a TFT display, you can set the display to one of three modes: Core, Full or Track. They each display different parameters on the screen — you can iterate through them to see which one suits you best.
Change the screen mode from the settings, accessing it by holding down the “confirm” button for two seconds when the bike is stationary.
Monster 821 Suspension Settings
Standard / Dark
The standard Monster 821 only has an adjustable shock. It’s adjustable for preload as well as rebound damping.
|Rebound||0 – 5 turns||1.5 turns||0.5 turns||2.5 turns|
|Spring preload||10 – 20 mm||15 mm||15 mm||15 mm|
Stripe / Stealth
On the Stripe and Stealth models, you can adjust compression and rebound damping in the fork, as well as preload. Preload is on both fork legs, but damping is only on the right hand fork leg.
Use screw adjuster on top of RH fork leg. Turn clockwise all the way to right, then back out.
|0 – 16 clicks||11 clicks||3 clicks||14 clicks|
Use screw adjuster on bottom of RH fork leg. Turn clockwise all the way to right, then back out.
|0 – 16 clicks||7 clicks||5 clicks||12 clicks|
Open all the way (anti-clockwise) with 14-inch wrench, and tighten in.
|0 – 10 turns||5 turns||5 turns||5 turns|
On the Stripe / Stealth models, the shock’s configuration is a bit different.
Fully close (turning clockwise) the screw on the shock. Open up for the settings shown.
|0 – 3 turns||1.5 turns||1 turns||3 turns|
Loosen the locknut and fully decompress the spring. Tighten to 15mm for the standard setting.
|10 – 20 mm||15 mm||15 mm||15 mm|
Ducati Monster 821 Service Intervals / General Info
The following came from Maintenanceschedule.com.
The Ducati Monster 821 has 9000 mile / 15000 km or annual service intervals. At every service, change the engine oil and filter, and run through the list of standard annual checks..
You should also change the spark plug at every oil service, and either clean or change the air filter.
The valve service intervals are every 18000 miles or 30000 kms. At these services, check the valve clearances and also change the timing belts. If you don’t do that mileage in five years change the timing belts at the five year point.
The Monster 821 is a liquid-cooled engine and has a hydraulic clutch as well as brake. Make sure you keep the service for the coolant and brake / clutch fluid up to date.
Ducati Monster 821 Maintenance Schedule
Below is a clarified version of the maintenance schedule of the maintenance schedule from the manual.
It’s separated into
- A regular maintenance checklist
- A periodic maintenance schedule, and
- An annual service checklist
There is also a separate section below on chain maintenance.
This is maintenance that you can do yourself (though the manual says you need a dealer to do it).
Using the motorcycle under extreme conditions, such as very damp and muddy roads or dusty and dry environment, could cause above-average wear of components like the drive system, the brakes or the air filter. If the air filter is dirty, the engine could get damaged. So replace/maintain those more often if you put them under duress.
Every 1000 km/600 miles OR 6 months (whichever comes earlier, perform the following maintenance:
|Monster 821 regular maintenance (every 1000 km / 600 mi or 6 months)|
|Check engine oil level (top up with Shell Advance Ultra if required)|
|Check brake fluid level (Castrol DOT 4)|
|Check tyre pressure and wear|
|Check the drive chain tension and lubrication (lubricate with Motul chain paste)|
|Check brake pads, replacing if necessary (front: 2x EBC FA630HH, rear: EBC FA266HH)|
Major Items Maintenance Schedule
Below is the service schedule of major items for the XXX.
- Observe the earlier of time-based or distance-based service intervals.
- Keep following it in the pattern shown beyond the end of the maintenance schedule.
- If you ride your motorcycle aggressively or in untoward conditions (e.g. off-road or in mud, rain, or on dirty roads, in stop-start traffic, or in cold weather without giving it time to warm up), you may have to service your bike more often.
|Km x 1000||15||30||45||60||Every|
|mi x 1000||9||18||27||36||(Months)|
|Conduct standard Ducati annual service (see below)||✓||✓||✓||✓||12|
|[D] Check the presence of any technical updates and recall campaigns||✓||✓||✓||✓||12|
|Change engine oil and filter (Shell Advance Ultra 15W-50, HF153RC filter)||✓||✓||✓||✓||12|
|Clean the engine oil mesh filter assembly||✓||✓||–|
|Check and/or adjust valve clearance||✓||✓||–|
|Change timing belts (73740252A)||✓||✓||60|
|Change spark plugs (NGK MAR9A-J)||✓||✓||✓||✓||–|
|Clean air filter||✓||✓||–|
|Change air filter (DU-1006)||✓||✓||–|
|Check brake fluid level||✓||✓||✓||✓||12|
|Change brake fluid (Castrol DOT 4)||36|
|Check frame-to-engine fasteners tightening (90 Nm / 66 lb-ft)||✓||✓||✓||✓||–|
|Check wheel hub bearings||✓||✓||–|
|Check steering bearings and lubricate, if necessary||✓||✓||–|
|Change front fork fluid (Shell Donax TA)||✓||–|
Ducati Standard Annual Service
Below is the standard annual service checklist. Do these service items according to the maintenance schedule above.
Items marked [D] require dealer-specific tools/resources.
|Ducati Standard Annual service|
|[D] Read the error memory with DDS and check of software version update on control units|
|[D] Check the presence of any technical updates and recall campaigns|
|Check brake fluid level|
|Change brake fluid (Castrol DOT 4)|
|Check brake disc and pad wear. Change, if necessary|
|Check the proper tightening of brake calliper bolts and brake disc flange screws (See below for torque specs)|
|Check the proper tightening of the rear brake disc and phonic wheel bolts (with removal of rear wheel shaft, if necessary) (See below for torque specs)|
|Check front and rear wheel nuts tightening (See below for torque specs)|
|Check the proper tightening of final drive front and rear sprocket nuts (See below for torque specs)|
|Check final drive (chain, front and rear sprocket) and sliding shoe wear|
|Check final drive chain tension and lubrication (Motul chain paste)|
|Visually check the front fork and rear shock absorber seals|
|Check the freedom of movement and tightening of the side and central stand (if any)|
|Visually check the fuel lines|
|Check rubbing points, clearance, freedom of movement and positioning of hoses and electric wiring in view|
|Check the free play of clutch lever|
|Lubricate the levers at the handlebar and pedal controls|
|Change coolant (ENI Agip)|
|Check the coolant level and check circuit for damage|
|Check tyre pressure and wear|
|Check the battery charge level|
|Check the operation of all electric safety devices (side stand sensor, front and rear brake switches, engine kill switch, gear/ neutral sensor)|
|Check lighting, turn indicators, horn and controls|
|[D] Reset the Service indication through the DDS|
|Final test and road test of the motorcycle, testing safety devices (ex. ABS and DTC), electric fans and idling|
|Softly clean the motorcycle|
|[D] Fill out that the service was performed in on-board documentation (Service Booklet)|
Checking and Adjusting Chain Tension
Ducati requires that you regularly check the chain tension and lubrication level.
To check the chain tension, measure the distance between the chain and the swing-arm. Follow this procedure:
- Put the motorcycle on its side stand
- Push the chain down (bottom segment) and release it.
- Measure the distance between the centre of the chain pins and the metal part of the swing arm.
- Repeat this process of measurement for several points on the chain by moving the motorcycle around.
Target drive chain slack: 28-30mm (1.1-1.2 in)
- Loosen the axle nut.
- Loosen the lock nuts on the adjuster nuts on either side of the axle.
- Turn the adjuster nuts to move the wheel backwards, tightening up the chain. pay attention to the adjuster markings. Make sure the wheel is aligned on both sides by ensuring that the adjuster markings are the same on either side.
- Grease the wheel shaft nut thread with Shell Retinax HDX2 and tighten it, together with the axle nut on the right hand side, to 180 Nm (133 lb-ft).
- Grease the adjuster screws with Shell Alvania R3 and tighten them to 10 Nm (7 lb-ft).
Ducati Monster 821 Tire Sizes and Recommended Pressures
The Ducati Monster 821 is a street sport bike, so would be good with anything from road tires through to sport tires with a minimal street-legal pattern. It runs a very conventional sport tire size, so there is a wide variety of tires available.
Here are the specified tire sizes and recommended starting point tire pressures.
|Wheel||Tire size||Tire pressure (cold)|
|Front||120/70 ZR 17||2.3-2.5 bar / 230-250 kPa / 33-36 psi|
|Rear||180/55 ZR 17||2.5-2.8 bar / 250-280 kPa / 36-41 psi|
Naturally, adjust the tire pressures as suit your riding style.
Tightening Torque specs
Below are some commonly needed tightening torque specs for the Monster 821. These come from the service manual.
|Engine oil drain bolt||20||15|
|Oil filter cartridge||11||8|
|Front sprocket retaining nut||190||140|
|Front brake caliper retaining screw||45||33|
|Front brake disc screws||30||22|
|Front wheel nut||63||47|
|Rear brake caliper retaining screw||25||18|
|Rear brake disc to phonic wheel retainer||25||18|
|Cush drive damper pin to driving flange, and rear sprocket to driving flange retainer||44||33|
|Rear axle nut (double sided swing-arm, but tighten on RH side)||180||133|
|Chain tension adjuster screws||10||7|
|Frame to engine (front and vertical head) retaining screws||90||66|
Alternatives to the Ducati Scrambler 821
The Ducati Scrambler 821, a middleweight sport bike from the late 2010s, was a contender in a popular category. Here are some of the bikes from its category.
Kawasaki released the Z900 to replace the Z800, but in some markets it also replaced the Z1000. The Z900 is an underdog in the class, but has a howling and highly engaging 948 cc four-cylinder engine that peaks in 91 kW / 125 hp at 9500 rpm. The rest of the bike is very well balanced, making it easy to ride at any speed.
Triumph has been a leader in the middleweight sport bike class for a long time with their Street Triple. In 2017, Triumph brought the displacement up to 765 cc, and gave the Striple a significant bump in power and specs, and expanded the range of bikes (between the S, R, and RS), with different engine specs. See the Triumph Street Triple buyer’s guide.
Yamaha has been making their now iconic MT-09 since 2014 and has made it in multiple generations. This second generation model with the 847 cc three-cylinder motor kept the stomping motor but improved some aspects of the suspension, well as revised the aesthetics. Yamaha also released a higher-spec SP version with improved suspension.
Other Related Motorcycles
If you’re interested in the Ducati Monster 821, you’re probably also considering other motorcycles with the 821 motor (including the Monster).
Ducati first used the 821 motor in two other motorcycles, the Hypermotard and Hyperstrada 821. However, those bikes suffered from a grabby clutch, which was rectified in the later-released Monster 821. (See here for must-do mods to the Hypermotard / Hyperstrada 821.)
Ducati used the 821 motor’s successor, the 937 cc Testastretta 11 degree, in a broader range of motorcycles.
Ducati first put the 821 motor in the Hypermotard 821 alongside the Hyperstrada 821. The Hypermotard is an upright sport bike with a compact dirt bike-like riding position, but with that sparkling L-twin. Pictured is the SP, that has a fully adjustable Marzocchi front end and an Öhlins shock.
The Hyperstrada has the same motor. It’s basically a base-model Hypermotard — with lower-grade suspension — but also with gear to make it somewhat touring-ready. It’s effectively the predecessor to the Ducati Multistrada 950.
The Ducati Monster 821 (pictured is the base model) is the last Ducati Monster to have a trellis frame, a part of its heritage since 1993. The 821 has a liquid-cooled Testastretta-11 degree engine, which has plenty of power for the middleweight.
Reference — Ducati Monster 821 Owner’s Manual
The above info was sourced from the owner’s manual for the Ducati Monster 821, consulting various years and trim levels. See screenshots below for reference from both the 1st and 2nd generation Monster 821.
You can download the manuals from the Ducati website here.