THE Monster: “M Ducati” S4R by Rob Maxwell

Ducati S4R Cafe Racer

“A ludicrous version of THE Monster…”

Introduced in 2003, the Ducati S4R was the most powerful Monster ever produced, featuring a liquid-cooled, fuel-injected 996cc L-twin derived from the company’s championship-winning World Superbike engine. This 113-hp Superbike engine was cradled in a lightweight trellis frame with fully-adjustable Showa suspension and a trick single-sided swingarm. Given the heavy-duty clutch and snappy fuel injection, the S4R’s in-town manners left something to be desired, but it was a hoot on the open road and through the twisties. Said Adrian Percival of Motorbikes Today:

“If I was to compare it with any other form of pure transport fun, then it has to be likened to a two-wheeled Shelby Cobra. It has a definite presence on the road, huge amounts of pure power and torque, unique looks and draws a crowd wherever it stops…”

Ducati S4R Cafe Racer

However, some aficionados felt the S4R had strayed too far from the elemental simplicity of the original Monster concept, creating an overly complex bike that no longer looked good naked. One such Ducastista is friend of the blog Rob Maxwell, whose Honda NX650 Desert Dominator we recently featured. Says Rob:

“The stock S4R for me is a bit of a mess, design wise…I wanted to take the bike back to its roots and clean it up as much as possible.”

Ducati S4R Cafe Racer

Rob replaced the bulky stock high pipes with a low-mounted QD Exhaust system, which revealed the lovely single-sided swingarm, lightened the bike 20+ pounds, and also served to lower the bike’s center of gravity. Brooks Suspension overhauled, upgraded, and anodized the stock forks, while he swapped the stock rear shock for an Ohlins unit. A set of @woodcrafttechnologies riser clip-ons dialed in the riding position, while Josie from @Jainsco supplied a new seat, and Rob details more of the modifications below.

“I guess it would fall under the café racer category, but for me it’s just a ludicrous version of THE Monster.”

Below, we get the full story and details on this “M Ducati,” along with more great shots from photographer @teuchterlife.

Monster S4R Custom: Builder Interview

Ducati S4R Cafe Racer

• What’s the make, model, and year of the bike?

Ducati Monster S4R, 2004.

• Why was this bike built?
Personal project
• What was the design concept and what influenced the build?

My good friend Gerry Harrison @theharrisoncollection had recently commissioned a bike from Callum at @debolexengineering. It was a customized Ducati 749 and it was an exceptional build (I think his best personally). Sadly I don’t have the type of capital to invest in such a build with a professional custom workshop, but I wanted to do something for myself. I have always loved the original Monster and I own an M900 from 1994 and a 695, both of which I keep in the highlands of Scotland. When I saw this S4R for sale in Glasgow for a good price and low mileage, I decided to buy it with the idea of doing some light modification.

The stock S4R for me is a bit of a mess, design wise. And I think Ducati lost sight of what the Monster was (after all, it was the bike that saved the company). The original Monster was born from a naked version of the 851 simply by removing the fairing and exposing the trellis frame and adding a round headlight. The S4R had lost this simplicity and become overly complicated. The single-side swing arm from the 916 was a great addition to the Monster but they then hid the beauty of this engineering by hiding it behind twin high-level pipes. The rear tail had become a monstrous piece of ABS plastic with big oval orange indicators and a long rear mud guard all to meet various new regulations. I wanted to take the bike back to its roots and clean it up as much as possible.

Ducati Monster S4R

• What custom work was done to the bike?

Firstly I removed the twin side pipes to expose the rear wheel with single-side swing arm. Then I removed all of the rear plastics and a section of the rear frame in order to put a hoop welded to the back. I didn’t want the new exhaust to cover any of the rear wheel so I looked for solutions to this and found the QD Exhaust. The beauty of this is that it sits right at the bottom of the bike, which lowers the centre of gravity as well as terminating before the rear wheel and exiting out to the side. By removing the original headers / cat box / rear pipes a savings of around 10 KG was made to the bike once the QD was installed. Not only that but it sounds incredible with the baffle removed.

Ducati S4R Cafe Racer

The stock bike is a lot heavier than the original Monster, mostly due to the 996cc engine block and radiator etc. Because of the extra weight the original suspension wasn’t really up to the job, so I replaced the rear shock with a fully adjustable Ohlins shock with damper and the front forks were sent to Brooks Suspension for upgrade and overhaul (they also anodized them in gold).

The stock bike comes with handlebars fixed to the top yolk much like the original Monster for a more upright riding position. This for me was the wrong setup — the bars felt like the needed to be lower / more aggressive, so I found @woodcrafttechnologies riser clip-ons in New York and had them shipped over. They are the perfect compromise for the bike, which is now more aggressive in its riding position but still more comfortable that an out-and-out sports bike. You now feel as if you sit in the bike rather than on it. To hide where the handlebar mount had been, I fitted a brass plaque nameplate.

Ducati S4R Cafe Racer

The original headlight and mount were removed, again making a significant weight saving, and a new Alu headlight and fork mounts were installed at a lower level to allow the original clocks to be mounted as low down as possible.

Motogadget bar-end indicators were used to remove the need for front and back indicators. Because the bars are wider than the rider you can pass MOT with just one set, meaning I only need a rear tail / brake light and nothing up front to mess the clean lines of the new headlight.

Finally the bike had a full custom paint — all gloss black with a subtle grey decal detail and pinstripe on the tank. The new seat was supplied by Josie from @Jainsco_ — she did a great job with the faux leather and grey stitching to compliment the tank. To finish off the bike a set of Pirello Diablo’s were fitted (the slickest street legal tyre I could find).

By removing many of the unnecessary parts and anything that carried excess weight, and at the same time adding the remapped sports ECU and exhaust, the bike is faster / lighter and far more nimble.

The M Ducati was finally alive!

• What’s it like to ride?

Awesome. It feels totally different to any other bike I own. It’s fast but manageable, much like the original 916. It feels much more nimble now that it has shed a few kg and the turn-in is much better due to the lower bar height. It’s a really nice bike to ride out on the country B broads and loves a fast windy A road all the more. It’s a bit of a handful round town mind you.

• Does the bike have a nickname?

I just called it ‘M’ so it’s the M Ducati. Could be for Monster / could be for Maxwell not really sure!

• How would you classify this bike?

Difficult to classify it; I guess it would fall under the café racer category, but for me it’s just a ludicrous version of THE Monster.

• Was there anything done during this build that you are particularly proud of?

I love the way it’s turned out when looking from the back of the bike forwards. Because there is no projecting exhaust, the bike is almost completely symmetrical — it has a very narrow stance which looks incredibly aggressive when you see it in person.

Builder Thanks

Photography @teuchterlife
Exhaust @QDexhaust
Tyres @pirelli
Clip-ons @Woodcrafttechnologies
Indicators and reservoirs @motogadget
Shocks @ohlinsracing @brooksuspension
Seat @Jainsco_

Follow the Builder @lucky.explorer


  1. Just want to comment regarding the QD exhaust as they seem to be very uncommon. I installed one on a friend’s Ducati GT1000 Sport Classic. There’s no direct application for that bike, but that bike has the same 2 valve air-cooled engine as some of the Monsters and Hypermotards, etc. It is a very light system, and in the case of the particular bike, which had two megaphone mufflers on either side the QD system shaved serious weight off the bike. The fitment behind the oil pan is neat, there’s plenty of space there. However, the system is LOUD. Unbelievably loud. Like Harley with straight pipes loud. If I recall it came with a restrictor plate that could either partly or fully block one of the two exits, my friend wanted the full volume experience so that was not used. QD claims there is a labyrinth inside the box, and I’m sure there is, but the thing is so light that baffling is quite minimal I’m thinking. It’s a very unique exhaust, but it is obnoxiously loud, and I doubt the restrictor plate would’ve made the thing civil. Slightly quieter, yes, but not civil.

  2. What are the mirrors?

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