Ducati Monster 821 (2015-2020) Resources — “The Hidden Manual”

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).

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
Cooling	Air/oil cooled	Liquid-cooled	Liquid-cooled
Capacity	803 cc	821 cc	1198 cc
Bore / Stroke	88 x 66 mm	88 x 67.5 mm	106 x 67.9 cc
Compression ratio	11.0:1	12.8:1	13.0:1
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 (same)	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.

Item	Specs	Notes
Engine type	Testastretta 11-degree, Liquid-cooled L-twin, Desmodromic 4-valve per cylinder	Similar layout to the contemporary 1200
Capacity	821 cc
Bore x stroke (mm)	88 mm / 67.5 mm	1.75 mm longer stroke than the 796 (803 cc)
Compression ratio	12.8:1
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
Display	LCD	TFT
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:

Setting	Options
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
Sport	High	1	2
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.

Parameter	Range	Default	Sport	Comfort
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.

Parameter	Range	Standard	Sport	Comfort
Compression damping 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
Rebound damping 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
Spring preload 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.

Parameter	Range	Standard	Sport	Comfort
Rebound damping 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
Spring preload 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

1. A regular maintenance checklist
2. A periodic maintenance schedule, and
3. An annual service checklist

There is also a separate section below on chain maintenance.

Regular 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.

Notes:

• 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:

1. Put the motorcycle on its side stand
2. Push the chain down (bottom segment) and release it.
3. Measure the distance between the centre of the chain pins and the metal part of the swing arm.
4. 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)

If the slack is out, adjust tension to bring it back into spec. You’ll need a breaker bar for the rear axle and a large torque wrench (that can do up to 200 Nm / 150 lb-ft).

1. Loosen the axle nut.
2. Loosen the lock nuts on the adjuster nuts on either side of the axle.
3. 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.
4. 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).
5. 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.

Item	Nm	lb-ft
Engine oil drain bolt	20	15
Oil filter cartridge	11	8
Spark plug	12	9
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.

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.

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.