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The chassis itself is actually quite stable and precise, where it gets into trouble is when the suspension and brakes come into play. In order to save on cost, the bike was produced with rather rudimentary suspension components which led to the forks being very soft and non-adjustable. The shock suffers similar fate, with loose valving, a soft spring and no adjustment other than a standard notch-ring style preload adjuster. Corners typically involve three things; breaking, turning and bumps/dips throughout the corner. At best, in OEM trim you can take on two of those…but definitely not all three if you're trying to ride at a spirited pace. On our initial ride of the 790 Duke, this was an area that stood out to us that needed immediate attention.
For the first time, KTM outfitted one of their street bikes with brakes other than their usual BREMBO caliper/master-cylinder combo, and chose to go with Spanish manufacturer J.Juan. Did they choose right? Let’s just say, we chose better. The OEM brakes had a decent feel at the lever as the initial “bite” was gentle and gave absolutely no sense of wanting to lock-up. The drama from the brakes came from wanting to do anything more than coast to a stop at a red light. The overall power of the brakes was very weak, on top of that, when trying to coax any more stopping power out of the system, the lever itself would squeeze nearly all the way to the bar. If you’re a one-finger breaker, that often meant smashing the lever into your other three fingers while hoping to slow down in time.
The engine actually has a great starting point, like many KTM’s, having power on tap that is smooth and potent is not a problem. But, we’re ROTTWEILER PERFORMANCE, there is NO WAY were leaving this area untouched! In fact, first thing we did with this bike (like every bike we get) is take off the tank and dive right into the intake system and see how we can breathe more life into this ½ size Duke. From there we go to the tuning, in order to have the best performance bike we can build, we need to start with the best stock platform we have. Typically, we will dive into ways to make the stock bike perform more efficiently, which has a side-effect of more power and cooler running engine temps. Next we dive into the exhaust systems as this is an easy way to add horsepower, trim weight, reduce high sitting weight (muffler) and of course, improve looks and sound.
Now these are the basic breakdowns of any bike. Tackling this group on any motorcycle will reward you with a much more fun and livelier machine. But (we shouldn’t have to keep saying this) we’re ROTTWEILER PERFORMANCE, we not only have a catalog of parts to choose from using our vendors, but we also have an in-house machine shop and can make or modify anything we can dream up.
Keep reading to see what exactly went into sharpening “The Scalpel” and making it the performance machine it was meant to be.
- Stock vs. - Rottweiler Power Plate + Arrow De-Cat Full System + Power Commander
It’s a no-brainer that being the intake mad-scientists that we are, that this would be the first area we attacked. The intake track and the area to work with was significantly more difficult that on the larger v-twins of past and current, nevertheless, we tirelessly went to work designing and testing. Below you will see our initial “Stage 1” intake modification, The Rottweiler Performance Power Plate. Through imagination, design, development and testing, we have come up with an easily installed upgrade that significantly improves the performance of the 790 Duke, providing both torque and horsepower gains while smoothing out the powerband of the parallel twin.
In order to further decrease the weight of the bike and increase the performance, we turned to ARROW Exhaust for a full competition exhaust system. This involved the installation of an Arrow Stainless Header, stainless de-cat mid-pipe and Ti-Carbon Muffler. The ARROW header provides weight reduction by using a thin walled steel and by simplifying the design as well. To take the battle against heat one step further, we ceramic coated the headers, a service we offer on many of our Arrow exhausts.
The weight really starts shedding off the bike by swapping out the heavy and heat soaked OEM mid-pipe which features the Catalytic Converter. If you plan on tracking or racing your bike, this is an absolute must. The Arrow de-cat mid-pipe is a “true through” unrestricted design that allows for maximum exhaust flow. The mid-pipe does feature a resonator chamber to help balance and tune the exhaust note ever so slightly.
Finally, we rounded out the exhaust with an ARROW RaceTech Titanium Muffler. By swapping out the OEM muffler you get a bike the actually sounds like a motorcycle, and a significant weight reduction. We have a many different muffler options, varying in both construction material and size, each having a slightly different exhaust note than the other. However, all ARROW mufflers include a removable “DB Killer” that is held in by a snap-ring, when installed this insert really cuts down on the decibels and smooths out the power delivery slightly.
In order to get the most from our Rottweiler Performance Power Plate bringing in additional air, and the Arrow full system flowing exhaust gasses more efficiently, we turned to DynoJet to allow us to map the perfect AFR (Air Fuel Ratio). We installed a full DynoJet suite starting with the Power Commander 5 as the brains of the operation.
While we have mastered the art of tuning KTM’s, there are still the natural occurrences that can affect our hard work (altitude, air temp, humidity, etc). For this we installed the DynoJet AutoTune Dual Wide Band system to ensure that all our dyno time is not hindered by the elements. What this means, is that whether you're riding in 100 degree weather at sea level or 50 degrees at 10,000 feet, the wide-band AutoTune sensors constantly check and re-check to make sure that your bike is always hitting the targeted AFR’s. This not only gives you the best performance possible, but also maximizes engine and fuel efficiency.
To keep an eye on everything and see how it's performing in real time, a POD-300 Data Logger was added. The POD-300 is a great addition to the family. When added, it can display any of the channels that are being tracked such as RPM, throttle position, injector duty, percentage of fuel alterations, ignition advance, air fuel ratios (requires Auto Tune) and more.
Being that suspension was a key area of interest, we dove right in with a MATRIS 25mm Fork Cartridge Kit and a MATRIS rear shock. Both units offer exactly what is needed by an enthusiast of any riding level. Starting with beautifully machined fork caps and pro-load adjusters, to the machined shock body, the craftsmanship is exactly what we expect from products that make it onto our builds. Additionally, both fork cartridge kit and rear shock allow the rider to change spring rates, adjust pre-load, compression (fork only) and rebound, key adjustments that are absent on the stock WP components.
Even though many bikes nowadays come stock with steering dampers, many offer the bare minimum in terms of performance and rarely ever are they adjustable. The OEM damper on the 790 does decent job of reducing minor headshake, but don’t expect it to take on much more than that. Sticking with our choice of suspension, we installed a MATRIS Race Replica Steering Damper that is very trick and mounts up perfectly. It has a wide-range of adjustability to tune the steering resistance to your desired preference, a ti-nitride coated shaft for ultra-smooth performance and can be rebuilt, shall you ever need that.
Flex from the front end can leave a wandering and imprecise feel both at corner entrance and holding line mid-corner. We for one, don’t think a wandering scalpel is remotely safe. Luckily KTM has a solution for this directly from their POWERPARTS catalog with a full Billet Triple Clamp kit, which not only looks drastically looks better, but increases rigidity for better handling and improved rider feedback.
As mentioned earlier, the brakes needed significant attention…more like, a complete overhaul. Being that they already struggled to stop a bike that was hindered by the limits of the OEM suspension, we knew with a performance suspension package, speeds would increase as well and therefore, would need extra effort to be slowed down.
One great thing about KTM is that they keep things fluid across multiple platforms, so many parts can be interchangeable from model to model. Take our “1290 BEAST ADV” build, since that bike is basically a SuperDuke in an ADV bikes clothing, we swapped out the OEM BREMBO calipers to the BREMBO M50 calipers found on the 1290 SuperDuke. Fortunately, this left us with very good quality OEM BREMBO units that had just been ageing gracefully in a drawer that fit right up to the almost standard 100mm spacing that most radial KTM brakes have.
The front brake system from the 2018 1290 ADV fit effortlessly on the 790 Duke with no modification needed, even the OEM brake lines mounted right up. This is an instant and incredible fix to the lackluster J.Juan brakes that come stock. The best part is that if you want to do this at home, you can easily find OEM Brembo units online for much less than what you think.
For the master-cylinder we swapped out the OEM unit with a BREMBO RCS 17mm Radial Master Cylinder which has an adjustable cam to tune your lever feel to your personal preference.
Rotational mass is one of the forms of weight that can have the greatest effect on the bikes handling and overall performance, and there is no other area on a motorcycle that has a larger rotational diameter than the wheels. Likewise, the weight of each wheel affects the bike slightly different, front wheel weight will affect the way the bike tips into corners (heavier front wheel, heavier steering feel), and rear wheel weight will affect how the engine spools up (lighter wheel, quicker acceleration).
For this we removed the OEM wheels and added a set of DYMAG UP7X Forged Aluminum Front and Rear Wheels, at a massive weight savings per wheel, they greatly increase both handling and performance, while adding gorgeous GP look to the bike. The decrease in wheel weight is also beneficial as it helps to offset the slight increase of rotational mass that was added by going to oversized front rotors. We finished off the wheels with a pair of Dunlop's latest DOT Supersport tires, the Dunlop Sportmax Q4 120/70-17 up front and a Sportmax Q4 180/55-17. These are ultra sticky and damn near Dunlop's AMA Supersport race-spec tire, just for the street.
While we didn’t need to change out the chain and sprockets, we did so for the sake of reducing weight and getting a little more response from proper final drive ratios. Since the 790 Duke already comes with 520 chain and 16/41 sprockets, we were able to leave the countershaft sprocket stock, but still we swapped out the heavy OEM chain for a lightweight DID ZVMX Gold Chain, and did away with the stock steel 41t rear sprocket and installed a 42t Talon Aluminum Sprocket. This combination allowed us to both remove weight and perk up the acceleration.
* keep in mind, when adding performance products like the power plate, a full exhaust system and performance fuel mapping, your bike will be able to pull a taller gear much easier. For this reason, we only went up one tooth on the rear, rather than go down one in the front.
One of the easiest and most cost-efficient ways you can remove unnecessary weight from your bike is to replace your heavy OEM battery with a lightweight Antigravity unit. For the 790 Duke an Antigravity ATZ-10 Re-Start battery is a direct drop-in replacement. With more cranking amps, universal post design, a “jump start” feature built in AND an average weight reduction of over 5 lbs, installing this battery will shed more weight per dollar than any other item. We install an Antigravity battery on EVERY shop bike we build, both for reliability and weight savings.
ROTTWEILER Performance Transaver
The KTM LC8 790 engine is an amazingly small and well-engineered engine, but the downside to this engine is that one can be easily bend or damag shift components. One ill-placed or hard downshift can bend any number of items in this system quite easily.
Our Rottweiler Performance Transaver is a unique and simple device that has identical feel in both up and downshifting when regular down pressure is applied, but when over-stressed has the ability to compress the gas strut momentarily in order to save the delicate parts in your transmission.
MAGURA Hydraulic HYMEC Clutch
Something KTM has been known for over the years (particularly on the motocross and off-road bikes) has been their usage of hydraulic clutches. Something that was not included on the 790 Duke was…a hydraulic clutch. It’s an obvious reason why though, cost. Cable clutches are significantly cheaper and simpler than their hydraulic counterparts. However, Magura recently released their HYMEC Hydraulic Clutch Conversion Kit for the 790 Duke that mounts up with no modification and brings back that buttery smoothness of a hydraulic clutch.
Not just some flashy hose. SAMCO Hose Kits, offer increased flow by using a silicone compound that reduces internal surface friction, thus allowing coolant to circulate more efficiently and keeping engine temps down as much as possible. They also have better insulation, so your radiator fluid isn’t as affected by engine heat as compared to stock.
For years we’ve been selling Evotech products and with each new model KTM releases, we are continuously impressed with the ingenuity and craftsmanship that comes from this UK brand. For our 790 Duke build we threw the Evotech catalog of accessories at the bike to clean up some areas and add much needed protection to others.
EVOTECH PADDOCK STAND BOBBINS - EVOTECH CRASH BOBBINS - EVOTECH RADIATOR PROTECTION -EVOTECH EXHAUST HANGER BRACKET (PASSENGER PEG DELETE) - EVOTECH TAIL TIDY - EVOTECH BRAKE & CLUTCH PROTECTION - EVOTECH CRASH PROTECTION
One of the many great things about KTM is that they are one of only a few OEM’s to actively pursue and manufacture accessories for all of their motorcycles, which as you would imagine, have flawless fit and finish. Parts installed:
KTM HARDPARTS REAR SETS - KTM HARDPARTS CARBON FRONT FENDER - KTM HARDPARTS 790 DUKE DONGLE - KTM HARDPARTS BILLET FUEL TANK LOCK CAP - KTM HARDPARTS PILLON (passenger) SEAT COVER - KTM HARDPARTS STANDARD ERGO SEAT - KTM HARDPARTS ENGINE SPOILER
Gone are the bulky and flimsy OEM turn signals, since we wanted the 790 to be in “race trim” as much as possible, we opted for a set of YOSHIMURA LED Turn Signals to minimize the signal footprint, while increasing the signals visibility.
We’ve been using C.R.G. Arrow Quick Flip Mirror Kit on all our bikes due to their sleek design and their ability to vastly improve the looks on every model. Additionally, on some bikes, removing the “mickey mouse ears” that are the OEM mirrors can reduce some of the buffeting felt through the handlebars at higher speeds.
While naked bikes allow the inner beauty of the bike to shine through, unfortunately, it also exposes vulnerable parts to crash damage. For example, the waterpump on the 790 Duke sits front center ...er side, of the 790's engine and right in an impact zone during a fall. The WoodCraft Waterpump Protector mounts over the OEM waterpump keeping it safe, and with a replaceable aluminum crash slider, you can make sure that there is always enough material between the asphalt and your bike.