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MD Project Bike: Dirck Modifies a 2019 KTM 790 Adventure

790 Adventure with OEM KTM 19″ front wheel

I have owned several street bikes over the years, but unloaded all of my personal motorcycles several years ago when I barely had enough time to ride test bikes in the MD garage (sometimes totaling as much as six). Recently, I got the bug to purchase, and modify, a bike and, after much thought, decided on a 2019 KTM 790 Adventure (the standard model, not the “R”).

Why did I buy a KTM 790 Adventure? As you can see in the review MD recently published, there are several things about this bike that I thoroughly enjoy. The bike is comfortable (upright riding position with decent leg room and wind protection), has an awesome motor (with surprising power given its displacement, and a firing order that sounds great and feels great), is practical (featuring a 5.3 gallon gas tank and excellent mileage), and a blast to ride (in part due to that motor and a very light weight).

MD’s stock 790 Adventure test bike

I purchased the bike with my own funds from a local dealer, rode it stock for roughly 500 miles, and then began a series of modifications – which I will discuss in multiple articles, including this one.

Things I didn’t like about the stock bike include the front fork, which has overly harsh initial travel (transmitting far too much impact to the rider when traveling over small stutter bumps and other obstacles). After that initial, harsh travel, the fork can actually bottom too easily when ridden off-road aggressively. Clutch actuation is a bit sudden (which can be dialed out by changing the leverage ratio at the clutch basket housing), and shifting can feel a bit vague.

Given my goal to create a bike that could challenge sport bikes on twisty, canyon roads, I also didn’t like the 21″ wheel and its narrow contact patch (the stock tire is a 90/90 x 21). Although grip on the road from the stock Avon tires was decent, I wanted more street-focused rubber.

Our garage project included removal of the front forks for fitment of new springs and valving

The first thing I looked for was a 19″, tubeless front wheel. I carefully considered building a custom wheel with steel spokes laced to either an Excel rim or a stock KTM tubeless rim (from an 1190 Adventure, for instance). The cost of doing this was quite high. Decent wheels built this way can run $700, or so, before buying brake discs to mount on them (several hundred dollars more). I also wanted a quality tubeless design, and wasn’t too thrilled about converting a dirt bike rim (such as an Excel) to tubeless with a kit (although I understand they can be quite reliable).

The more I looked at it, it appeared that the stock KTM 1290 SuperAdventure S front wheel would fit on the 790 Adventure. That wheel is a cast, 19″ tubeless design (pictured). Although I discussed it with a local dealer (who contacted KTM headquarters), I was told the wheel wouldn’t fit. I convinced myself that it would, however.

Test fitting the new 19″ front wheel

I compared the parts online – the axle and axle-spacers are identical for both front wheels, and I measured the distance between the brake discs at the local dealer, and the disc spacing was also identical. In addition to being a tubeless OEM design, the big benefit was that this wheel is dirt cheap compared to the alternatives.

I bought a complete 1290 SuperAdventure S front wheel for $350 (brand new) on sale, which included bearings and all of the internal pieces that I thought would permit the wheel to be bolted directly onto my bike. This wheel also appeared to allow me to transfer my brake discs and ABS ring from the front wheel on my 790, saving substantial, additional cost.

Despite all my research, I was a little bit nervous that the new wheel wouldn’t fit. I took the brake discs and ABS brake ring off my 790 and they bolted perfectly to the new wheel! Step one was a success. I then test fit the new wheel, and it also fit perfectly! Success!

To our eye, the bike looks good with a 19″ front wheel – even the fender gap looks good!

I then began to research tires. I wanted to maintain my 18″ rear wheel, so I also plotted out adjustments to steering geometry and weight distribution given the smaller diameter front wheel.

As delivered, my stock bike had the forks mounted with more than 1-1/2″ of fork height adjustment available to me (the fork tubes were 14 mm, or so, raised above the top triple clamp). This would allow me to raise the front end to partially compensate for the roughly 1″ drop in front axle height resulting from the mounting of a 120/70 x 19 front tire.

I found good street tires in a lower profile 18″ diameter – allowing me to change the rear tire from a 150/70 to a 160/60. This would drop the rear end, and put me in the ballpark of the stock geometry and weight distribution. I could further fine-tune this with rear shock preload changes. I’ll talk more about the tires I chose (Continental RoadAttack 3), and other modifications to the 790 Adventure, in a future article. Stay tuned.

60 Comments

  1. Djevelsbror says:

    Hei,

    Se no point in all this mods, by a T800XRT 2019 instead, You got all in price. Good luck…

  2. Jeff says:

    Did the same thing a couple years ago with a 2016 Triumph 800 Tiger XCx I had. Bought a new Xr cast front wheel and a used take off rear wheel from a frontal crashed XR. I then added some Bridgestone A21 tires, upgraded the suspension for my 225# weight and the bike was transformed. Didn’t regret it a bit.

  3. Josh B. says:

    I forgot that there were all those spy shots of the 890 Duke GT/SMT last fall. That kinda of makes this project a needless pain in the butt right now.

  4. david novick says:

    I’ve been following this site for years, or is it now decades? Real-close. Anyway, I hope to see content continue on a more regular basis, but I totally understand the life issues get in the way, and that making $$$ in the motorcycle industry is really tough. I spent 6 glorious years at Kawasaki in SoCal – riding everything, but pay was less then stellar. Anyway, thanks for all that you do, and wishing you the best. Seems funny, but with everyone at home – now might be the perfect time to do ANY motorcycle project you’ve dreamed of. Order parts online, Ship em in, and craft away. I may just build an electric motorcycle now, as they’re pretty interesting. Best to all!

  5. Tommy D says:

    I just got my 790AdvR back from its first service yesterday. I had the cruise control and heated hand grips added while it was there. Those heated grips really throw heat and are top notch although the control should be integrated into the bike better. (Like Ducati’s use of the starter button once running)

    I’ll be interested in your choice for luggage. Do I see a detachable top case in the future?

  6. Gunner says:

    Sad to say, but KTM simply is not on the same level as Honda when it come to overall build quality. I ride a modified Africa Twin and enjoy every minute, specially doing the winter service. Taking anything apart on that bike is pure joy, everything works and keep on working. The european manufacturers can not compete with top jap bikes, or perhaps any jap bike. And it’s been like that for decades.

    • todd says:

      I’ve said this before but I’ve had all sorts of problems with Hondas. Lots of catastrophic failures and needless expenses. I’ve had much better luck (like zero problems) with Yamaha, BMW, and KTM. I now have put well over 300,000 miles on motorcycles, and a small portion of that was with Hondas.

      • mickey says:

        You are one of the outliers todd. One of the odd one’s out. For the vast majority people, it’s the other way around. A fact proven that Honda’s are widely known for their reliability. In 54 years I probably have over 600,000 miles on Japanese bikes (mostly Honda’s, then Yamaha’s but some Suzuki’s and Kawasaki’s too) and another hundred thousand miles on American, German, Italian and British bikes. Never had a Japanese bike fail to bring me home. The American, and Italian bikes were the absolute worst in reliability for me.

    • Jeremy says:

      KTM competes, but their emphasis is on performance above all. Lighter, more powerful things need more maintenance and break more often. Just the nature of the beast. I think most KTM buyers accept the compromise inherent in this approach.

      Now the Italian stuff? Well, that’s a whole different kind of compromise and requires a strong stomach. A penchant for denial and self-deception are also very useful character traits if one wants to own Italian.

      • mickey says:

        Careful Jeremy, you are poking the “I’ve had my Ducati for 20 years and it’s been the most reliable bike I’ve ever owned” guys lol

        • Pedro says:

          You Too! I do love my ducati , but I am under no illusion that it is up to Japanese manufacturing and engineering standards. But they do have specific point of view, and I like that point of view.

          This filling of niches is what the Euros do because they cannot match the build quality, nor the testing and design , of the Asian makers. Everyone has their part in the eco-system.

          But KTM – strangely seems to be about 20 years behind in construction standards, and gets a pass. Like the bikes – the owners …LOL – stay off the forums…

  7. Rapier says:

    To my mind this is the perfect bike for the age. I wouldn’t bother with the wheel thing but that’s just me. For the average rider who just wants to ride, the highways mostly, to go out and see the world on the wonder of our age, open roads through and to everywhere, the big wheels still work just fine. Embrace the limitations of your machine, that’s where skill lies, and fun.

    And the roads aren’t getting any better.

  8. Anonymous says:

    I have a second set of wheels for my KTM 690 Enduro which are a 17″ rear and a 19″ front. This is like have two bikes in one. Once you get it all set up the changeover can be done in 30 minutes. It was a good and the bike handles like it is on rails when riding on the street.

  9. Anonymous The 1st says:

    So why did you leave the rear wheel a tubed one? That makes no sense. And yeah, it’s a valid question to all you that feel otherwise.

  10. Ilikefood says:

    How does the wheel size change impact the ABS and traction control system? I imagine that these systems are finely tuned to measure differences in speed between front and rear wheels and changing wheel diameters could cause problems? If that’s not the case that’s awesome, I’d love to be able to get an 1190 Adventure and put 17” wheels on it, and still keep all the fancy ABS and traction control electronics.

    • Dirck Edge says:

      I am changing the abs rings. This will be discussed in a future article. My speedometer error is close to 12% currently. The new abs rings should correct this. I believe my TC is currently working, however.

      • Curt says:

        I look forward to your comments on the speedo error and ABS rings. I suspect the speedo is at least 10% off on my 1290 and I’ve love to learn of a remedy.

        • TF says:

          There are a couple guys who frequent the ADVRider KTM forum who make custom abs rings. If I remember correctly, mine were made by a forum member over in the UK. My 1090’s speedo is very accurate now with the 19/17 wheelset.

          No issues with TC or ABS functionality.

    • Walter says:

      Fwiw, the 19/17 seemed to have no affect on ABS when installed on the 990 (using the same ABS ring as the 21/18 wheels). The 990 didn’t have TC, but iirc folks with 1x90s that have done wheel swaps haven’t listed issues.

  11. Josh B. says:

    Yes, a 790 Duke GT would be my ideal bike! As long as they don’t make it too cramped in the legs for taller people like the Super Duke GT…

  12. marloweluke2 says:

    I would love for KTM to build 790 Duke GT. Sort of the direction Dirck is heading.

  13. Redd Dawg says:

    Looks like a lot of work trying to build a Yamaha Tracer 900.

  14. Walter says:

    Congrats! You’ve (almost) built the ideal bike KTM should. Just need a 17″ rear now.

    I had a 19/17 setup on my 990 Dakar, and bought an 1190A when they came out. Been waiting on KTM to do a 19/17 790 (or Honda to do it with the AT). As an aside, using a 17″ rear keeps the geometry pretty similar– like pretty much everyone else who did the conversion- I felt the bike handled like it was made for a 19/17 setup.

    For the vast majority of users a 19/17 is better than a 21/18 because most people spend a lot more time on paved and gravel/dirt roads than really off-road where the 21/18 is better. And the 19/17 tire choices are wider– from pretty agressive dirt biased to 100% pavement.

    Not saying to do away with the 21/18- there are folks that could use the 21/18 (or at least want to have that image of themselves lol): but 19/17 really hits the sweet spot for most folks.

    And the real mystery is why KTM does standard versions of the 1×90 (except the AT-fighting 1090) with 19/17 alongside the R versions, but didn’t do it here. Would seem to be pretty trivial for them.

    Anyway- congrats again and I look forward to hearing how you like it.

    And see if you can get a 17″ rear wheel solution lol

  15. Curt says:

    Cool project. Looking forward to seeing what else happens. I thought wheels were going to be way more expensive. Been thinking about setting up another set, with knobby tires on it, for my ADV bike and now I will for sure. Great info!

    • Dirck Edge says:

      I could have easily spent $2000, or more, building a 19 inch front and a 17 inch rear wheel, with brake disks to fit a custom hub.

      • Curt says:

        That’s what I’d have thought. But it looks like it’ll be closer to $1000, before tires and mounting, for stock wheels for the 1290 Super Adventure S. Sounds good to me.

      • TF says:

        I did the same with my 1090R so I can save the wear on the off-road tires when we take longer road trips. I paid $600 for a (new) set of cast wheels from the 1290S……I get the employee discount on parts as I have a family member who works for a dealer. I also had new abs rings made with one less slot. Now my speedo is dead nuts accurate when compared to GPS. Having two wheels sets makes the bike so versatile.

        • BGH says:

          How do like the handling with the 19/17s?
          I’ve considered doing the same with my 1090, but there are some naysayers who claim that the bike will handle poorly with the reduced trail.

          • TF says:

            On the street It handles a bit quicker but still plenty stable. I have not ridden off road with the 19/17 combo since I bought them strictly for street tires. It’s a pretty quick swap back to the 21/18 wheels even with having to change the brake disks over. I think being able to quickly swap between street and dirt tires/wheels is the biggest benefit.

        • BGH says:

          Thanks. How about the side stand? Do you have to be careful how you park it or do you have a cut down stand?

          • TF says:

            Yes, you do have to be careful when parking the bike and it’s a bit harder to put it up on the centerstand, if you have one. I have seen where someone makes a sidestand foot that is adjustable. I may buy one of those.

  16. MGNorge says:

    Interesting, looking forward to your end results and opinion.

  17. Reginald Van Blunt says:

    Vision, sharply executed with courage to chance. Nice.

  18. Mike says:

    Exactly what I would do if I owned that type of bike, in fact I did something similar to my 620 dual sport. But up fron I laced a 17 inch spoked rim to the KTM hub . Great choice of tires as well. The RA3 rock.

  19. Mick says:

    And here we have the rare glimpse of the journalist/owner devide. Read all the reviews you want on the 790 Adventure, you’d be lucky to find one saying that the tuning on the fork sucks.

    Journalists usually save comments like that for a few years, after the fork has been changed on a newer model.

    • Dirck Edge says:

      A little context here. First of all, I don’t think the stock fork tuning “sucks“. I stand by my original review of this bike, including my comments on the fork tuning. I could’ve purchased any number of motorcycles, but I chose the 790 adventure because I thought it was a great bike, for the reasons stated in the article. No bike, however, is perfect show room stock. The modifications I am making to the bike reflect my personal preferences, given my experience with motorcycles, my intended uses of this bike, And my personal riding skill level.BTW, I thoroughly enjoyed riding the bike bone stock, both when I reviewed it and for the first 500 miles on the bike I bought.

    • Mick says:

      Nevertheless, one would expect to see something about soft springs and an over abundance of rebound dampening in some review somewhere if some guy who is swapping wheels for better street rubber is tuning his fork for better off road prefomance.

      I’m not criticizing you. The motorcycle press has traditionally glossed over foibles that owners address. I think it’s simply because few writers would dare to assume some little flaw that they might find in a bike would be the same flaw that a lot of other people would find. How long did the dohicky issue on a KLR 650 take to get reported?

      It’s never easy to tune a good supermoto fork. Getting the right rebound profile is illusive. Good luck!

      • Dirck Edge says:

        Thanks Mick.

      • TimC says:

        Yes, it’s basically the truth that (in the US especially, I’ve seen UK mags be a lot more frank) reviewers can’t say too much bad stuff. And it’s exactly right that they somehow can once they are talking about how the new one fixes those things! It drives me nuts. So yeah I certainly didn’t take this as any criticism of Dirck specifically, more just How It Is generally.

  20. todd says:

    Fun project. I got the 690 Duke because the 790 wasn’t really any faster for me and I liked the quicker/lighter handling. Both are super fun bikes though. It’s good to hear about your personal side, Dirck!

  21. VFR Marc says:

    At last – an interesting and informative article of relevance to day-to-day riders. Good luck with the project.

  22. Mitch says:

    Bravo, Dirck! I’m very interested to get your bent on customizing a bike. A refreshing change of subject!

  23. Sub Pontem says:

    I put ’86 gsx600 forks and a custom 18″ wheel on the front of my ’82 XT550 and now it is a hilariously fun little roadster. Twitchy, but fun.

  24. Gary in NJ says:

    I think you made a great choice for a project bike. KTM builds exciting machines and the 790 platform is probably their best. I have 3 custom bikes in my garage right now…I’m hoping this series doesn’t give me any ideas and effect my wallet in a negative way.

    Looking forward to more.

  25. mickey says:

    Sounds like a fun little project. One of my nephews has a 790 Duke and says good things about it. Looking forward to future installments.

  26. Wally says:

    Why not install 790 Duke wheels front and rear and have a comfy sport bike?

    • Provologna says:

      Changing a dual sport with OEM 21/18″ to dual 17″ is a radical change in geometry, that would require commensurately radical (and even more costly) suspension mods to maintain similar drivability.

      I suspect, done right, the bike you suggest would be fun; but I also suspect it’s not what Dirck had in mind.

      • Gary in NJ says:

        “Radical”? Hardly. A little less trail and steering rake. Take a DRZ400 for example. The standard DRZ has a 21/18 wheel combination whereas the Supermoto version has 17/17. In fact, it’s very common for owners of those bikes to own both sets of wheels, swapping them out for the needed application.

        Sure, it’s a change, but it doesn’t require any changes in suspension to be done correctly. The spring cares little about it’s angle…same for the valving.

        • Provologna says:

          Considering differences in tire profile, the tire/wheel change you describe lowers the front end about 2.25 inches, the back end over a half inch.

          The difference in performance envelope between a DRZ and the 790 subject is yuge. Because that swap requires no suspension change (for you) on a positively ancient DRZ does not prove it would be the same on a 790 ridden by someone w/Dirck’s riding skill.

          The fact that you even post such comparison tells readers more about you than the subject you address.

          • Gary in NJ says:

            OK

          • Anonymous says:

            Jeez, Provologna, good job on the sanctimonious mansplaining.

          • Grover says:

            Depending on the skill and experience of the rider, he may not notice the rake and trail changes that much. Everyone told me how lowering my Dualsport with Koubalinks was a terrible idea, but the only thing I’ve noticed is that it’s easier to ride now that I can dab easier to prevent falling.
            Lots of Supermoto guys change their wheels back and forth regularly and are quite happy riding the bike with either wheel setup. Like I said, experience and skill level at the extreme end of riding (which most of us don’t do on the street or dirt) may show some deficiency, but most of us wouldn’t notice one way or the other. Also, testing the limits of adhesion on the streets is just plain old STUPID.

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