KTM Duke 690 mutates into a road racer

Discussion in 'Some Assembly Required' started by Singletrack_mind, Jun 11, 2016.

  1. Singletrack_mind

    Singletrack_mind Cave Man

    Joined:
    Aug 29, 2008
    Oddometer:
    493
    Location:
    Northern New Mexico
    [​IMG]

    Several years ago I had a 690 Enduro. Being an old road racer, just about every time I rode that bike I thought "wow, this engine would be so much fun on a track". Last winter I finally had to make it happen. I thought about getting an engine and putting it in some other frame; I have a Bare Bones Machine TZ Rotax sitting in the garage and considered pulling out the Rotax and installing the LC4, but that seemed like sacrilege considering how nice Jay's work on the BBM is, and also, it would not have been a simple thing. Further, with a modern engine, you need the electronics. I'd have needed the ECU, the throttle and throttle body, a pump suitable for the injection system . . . a good part of the wire harness . . . Easier to get a whole bike.

    [​IMG]

    Enter the 2014 Duke. I settled on the 2012-2015 generation because it had most of what I wanted; the slipper clutch, a nice light set of wheels, and until the 2016 came out, the most power. It turns out these bikes are not easy to find used. In the end I bought one brand new from a dealer for just under $6K, which is less than I saw used ones offered for.

    [​IMG]

    The Duke has a great frame to start with for something like this. I removed the entire subframe and made a new one out of plate aluminum. I chose to retain the stock wiring harness and not cut it anywhere, so there is a bit of extra electrical stuff tucked behind the seat, but there's basically nothing back there anymore. The battery is directly under the seat, I decided not to spring for a Li battery this season.

    The nose and tail are SebiMoto carbon kevlar 916 parts that weigh nothing at all. I just happened to have them around, so I decided to go with John Britten's "Bullet on a Blade" aerodynamic profile: no sides or dam around the radiator. The belly pan is a piece KTM makes for their cup race series in Europe.

    The engine has an Evo 1 kit in it: The map, the cam and the intake kit. I don't have the funds for an Akropovic, so found a much cheaper system from GPR in Italy. KTM claims 79hp at the crank like this. That seems optimistic and I have no access to a dyno, but it's pretty strong for a 700cc single!

    Fitting clip-ons was a challenge. The brake master cylinder is the old-fasioned cast type, and forced me to use longer bars than I'd like because it couldn't be slid far enough inboard. The tank also has strange 'shoulders' reminiscent of a dirtbike's radiator shrouds. These interfere with bar placement. I solved this by making re-location plates that slide the tank back 2-1/4". I also removed all the bodywork from the tank.

    [​IMG]

    I needed to fabricate a mount for the front fairing. I do not have a welder, so prefer to use other fabrication methods when possible. I chose rivets for this. The biggest challenge was arranging a way to fasten it to the frame of the bike. The headstock tube is very thin walled in the middle away fro the bearings, so it's not possible to tap into, and I wanted something more solid than rivets. I made up a bar of aluminum with two tapped holes in it and slipped it inside the steering head tube, then bolted into that. It's tight in there, but there's room. Those bolts are lock-tited, I do NOT want that coming loose! Making the instrument bracket was a treat, since the stock unit has all it's mount points in plane and is a nice little self-contained pod with vibration isolators. The stock wiring harness even reaches it in it's new location.

    One disturbing thing I'd been noticing while the bike was on the bench; the set screw holding the forged axle clamp to the lower fork stanchion seemed to be sweating oil. Sure enough, when I started moving the bike around, that became a definite leak. I tore apart the fork with some help from my friend Jason at SMR in Santa Fe and we fond that the O-ring at he base of the fork leg had a large section torn out of it during assembly. I needed Jason's help because these are weird forks. In fact, when I saw the internals, I got scared. They were so crude, and such an odd design. Even though they say "WP" on the outside, they are made by "WP Endurance", a subsidiary in India. I was a little freaked because I had expected we could re-valve them if necessary, but in general I had planned on running the first season on them. I wasn't sure I could do anything with what I was looking at.

    This is where David Behrend of Fast Bike Industries presented the solution: He imports Andreani cartridge kits from Italy; on the Duke, the Andreani kit replaces EVERYTHING, and you wind up with compression damping on one leg, rebound on the other, preload adjusters, and proper springs for your weight located at the top of the fork, not sitting at the bottom as unsprung weight like on the OEM design. The picture below shows the stock internals for one leg above, and the Andreani parts below. One final disappointment with the OEM forks is that even though they appear to have 135mm of travel, and that's the figure KTM gives in the manual, they actually only have a 110mm stroke.

    [​IMG]

    Anyway, that's enough for now. The bike's been racing two weekends now, and will head out again next weekend. I am in no way riding it to it's potential yet, but it's been fun so far!

    [​IMG]
    #1
  2. Lambo

    Lambo Been here awhile

    Joined:
    Aug 30, 2006
    Oddometer:
    724
    Location:
    Seattle
    Awesome job, looks really good. So how about some riding/racing impressions of how this is working out.

    Thanks,
    #2
  3. tobiism

    tobiism Adventurer

    Joined:
    Jun 28, 2011
    Oddometer:
    47
    Location:
    Chandler AZ
    Heck yeah that is awesome!
    #3
  4. dwdantzler

    dwdantzler Been here awhile

    Joined:
    Jan 8, 2015
    Oddometer:
    224
    Location:
    Brunswick, GA
    Glad to see the Fast Bike Industries information there. Dave is the best!
    #4
  5. racingxtc7

    racingxtc7 Been here awhile

    Joined:
    Dec 31, 2014
    Oddometer:
    134
    Location:
    Kenosha Wisconsin
    Awesome build. I had thought about building a 690 myself. CCS doesn't have any classes it would be competitive in. Ahrma does have a couple classes it would be more than competitive in though.
    #5
  6. Malcontent

    Malcontent Been here awhile

    Joined:
    May 3, 2006
    Oddometer:
    106
    Neat build. Any updates? What did you do for a rear shock? What does the final package weigh?
    #6
  7. Lambo

    Lambo Been here awhile

    Joined:
    Aug 30, 2006
    Oddometer:
    724
    Location:
    Seattle
    More Photos? Updates?
    #7
  8. Wildebeest90210

    Wildebeest90210 Long timer

    Joined:
    May 24, 2013
    Oddometer:
    2,027
    Well, while singletrack is AWOL this was my take on a 690 a few years back. Fierce :D

    DSC07096.JPG

    Attached Files:

    #8
  9. Sakel

    Sakel snark

    Joined:
    Oct 1, 2014
    Oddometer:
    54
    Location:
    there, now here
    Did you ever finish the efi setup on the mutant?
    #9
  10. Wildebeest90210

    Wildebeest90210 Long timer

    Joined:
    May 24, 2013
    Oddometer:
    2,027
    Only just good enough to ride then sold it on to a guy with epilepsy who couldn't legally ride it. I hope it's been well tuned by now and maybe one day he'll be good to ride. It was quite brutal :D.
    #10
  11. DRjoe

    DRjoe Long timer

    Joined:
    Sep 6, 2007
    Oddometer:
    7,032
    Location:
    Sunshine coast qld
    How the hell did that thing pass an mot with that noise?

    You've probably all ready said but where did you get the switch gear for that 690 beast?
    #11
  12. Highliner

    Highliner Adventurer

    Joined:
    Jun 27, 2009
    Oddometer:
    82
    Location:
    West by Gawd
    what was this? Is there a build thread?
    ?
    #12
  13. Highliner

    Highliner Adventurer

    Joined:
    Jun 27, 2009
    Oddometer:
    82
    Location:
    West by Gawd
    what was this? Is there a build thread?
    ?

    Really like the Duke transformation, those truss frames are my favorites.
    #13
  14. zeroblah

    zeroblah Snot nosed kid

    Joined:
    Aug 9, 2010
    Oddometer:
    431
    Location:
    Abq New Mexico
    Have you taken this bike to SMRI lately? I've been doing photos there the past couple months, would love to see this thing!
    #14
  15. Wildebeest90210

    Wildebeest90210 Long timer

    Joined:
    May 24, 2013
    Oddometer:
    2,027
    #15
  16. Rick4003

    Rick4003 Adventurer

    Joined:
    Apr 17, 2012
    Oddometer:
    25
    Really nice build! Would love to see more detail photos! Or just more photos in general :)
    #16
  17. Singletrack_mind

    Singletrack_mind Cave Man

    Joined:
    Aug 29, 2008
    Oddometer:
    493
    Location:
    Northern New Mexico
    Nice, the early Gixer frame is always a good place to stick a different engine. Who made the exhaust?
    #17
  18. Singletrack_mind

    Singletrack_mind Cave Man

    Joined:
    Aug 29, 2008
    Oddometer:
    493
    Location:
    Northern New Mexico
    Zero, I've not ridden this bike at Sandia. It should be my "home track" since I'm in Santa Fe, but I've always raced with the MRA in Colorado (I consider Pueblo my "home track"). The Duke should go really well at Sandia since it's all tight & twisty.
    #18
    zeroblah likes this.
  19. 65matt

    65matt Adventurer

    Joined:
    Dec 8, 2015
    Oddometer:
    63
    Location:
    Georgia
    Both of these are beautiful builds! I really like the riveted aluminum fabrication. Way better than I could have done!
    #19
  20. Singletrack_mind

    Singletrack_mind Cave Man

    Joined:
    Aug 29, 2008
    Oddometer:
    493
    Location:
    Northern New Mexico
    OK everyone, sorry I stirred up interest and then didn't follow up. Here's an update:

    I raced four out of the seven weekends with the MRA: Twice at Pueblo, once at Pikes' Peak (the road race track, not the "Race to the Clouds"), and once at High Plains Raceway. I got off to a typical start at PPIR. I'd had all winter to make sure everything was correct on the bike, but I showed up for the first race and sprung an oil leak anyway. I'd grazed the inside edge of the cap on the cam chain tensioner when I drilled it for safety wire, but it didn't really start leaking until I'd run the engine at high revs for a while. That caused a bit of frantic running around, but I was able to fill that hole with 5-minute epoxy and re-drill the cap. After that no problems, the bike had run less than 10 miles before it started racing so it got broken in on the track. I hadn't raced for 6-7 years, and didn't get much practice because of the leak, but at least at PPIR I felt right at home, remembered which way the track went. The bike handles great, I was impressed with the ability to put it anywhere I wanted at any time.

    Unfortunately, right after that race I learned that the company I'd worked for the past 19 years was closing down at the end of the summer. This put a damper on the rest of my season, since I knew I was spending money that I might later really regret if I couldn't find a new job. The next race was at Pueblo though, and at 4 hours away it's the closest race, one I was definitely going to. I began to get a handle on the starts, and at Pueblo there is a long front straight, plenty of time to put my straight-line skills to work. It's really embarrassing how much more power I have off the line than most of my competitors, but my corner entry is another thing. The Duke should be able to go way, way deep into a corner and in the old days, so could I. This season however I never re-gained the ability to do that. It was frustrating, and I made small improvements, but really let myself down by not capitalizing on the bike's strengths. So, the races were hectic, with me getting right to the front at the beginning, and then slipping backward most of the race. I still had some good fights though, because often a less powerful bike could pass me in the T6-T7 area, but then I could pass them back in the next half a lap under power.

    HPR was insanely hot, I think it hit 104˚ both days, and this was the weekend of the 4-hour endurance race! I did not enter that though for lots of reasons, but one big one would be fuel. The Duke sucks that tiny tank dry very quickly at WFO. Another reason is vibration. About 4 laps into an 8 lap race, I am having real trouble feeling the throttle and front brake lever. I've ridden a lot of racebikes that vibrated pretty hard, but this is the first one that I haven't just gotten used to.

    Riding HPR was one of my goals for the season. Unfortunately it is 7-1/2 hours away, so making it happen is tough. I am so glad I did it though, and made time for the track day on Friday before the races to learn the track. It's wonderful. The MRA built this along with the Colorado Sports Car Club, so it was designed by and for motorcycle racers. There are all kinds of turns and lots of grassy run-off, nice pavement and pretty blue & white low curbs where you want them, not where you don't. I got comfortable on it more easily than I had expected, and began to reach the limits of the suspension. I had been focussed on the front end, and worked a lot to make best use of the fork with it's new internals; key there was to drop the oil height a long way below stock. I was still having a high-speed bouncy feeling mid-corner, a chattery un-setled feel on braking, and began pushing the wheels in one tight hairpin. Lowering pressure in the Pirelli Diablo slicks helped, but I realized that the rear shock was both terribly under-damped, and quite easy to bottom even while giving me correct sag numbers. Another problem with the OEM shock is it's completely non-adjustable, and I want more ride height in the rear. The swingarm needs more downslope, and jacking up the rear might allow me to pull the front back up some, gaining ground clearance. I have rear-sets on the bike, but am still dragging my toes. Before HPR I added solid-mount pegs to the KTM rearsets which come with folding pegs. When I did so I mounted the new pegs a little higher for clearance and caused another problem; I began missing shifts. I could dial the shifter down to ensure safe up-shifts, or adjust it up to make sure of my down-shifts, but the happy medium was hard to find. My foot is just a tiny bit further from the shifter.

    Pueblo was my final race of the year, and there was no drama from the bike. However, in Pueblo it was evident people had been paying attention to the Duke, and seeing it for what it could be even if my finishing positions weren't that great. On the one hand there were a few guys on the 350s who are beginning to grumble about the "unlimited displacement single cylinder" eligibility in one or two Lightweight classes. On the other hand, two other KTM 350 Cup riders went "hey wait, that's LEGAL?" and showed up with brand new 690 Dukes. Boy did they go! They'd been fast on the 350s, so they were cream of the class on the Dukes. I will be very curious to see what shows up next year, it sounds like there could be a half a dozen of us suddenly. Pueblo also marked the fourth weekend on one set of slicks which is awesome, although there was definitely a drop in outright grip after the first weekend.

    I am still without a job, although I am finding lots of freelance work. This means I am planning to race again next year, but haven't bitten the bullet and laid out the money for the two things the bike really needs: A new front brake master cylinder and a rear shock. I have already added bar-end weights, and rules will require lever protectors starting next year so I am hoping the extra mass will help with the hand numbness. The stock master cylinder is really poor quality, very sloppy lever feel and also it's cast-on reservoir forces me to run wide bars. Replacing that should help with precision going into corners, with the stock controls my transition from throttle to brake is very vague and sloppy. The other half of this is a great deal of slop in the throttle assembly. Since it is RBW and not a cable system, I have not yet figured out a way to get rid of all the excess play. The need for the shock is obvious. I'd dearly like to get a light weight Vortex gas cap too, the stock keyed unit weighs a ton, requires the key which surely some day I'll forget (I removed the OEM ignition switch), and is super annoying because it won't stay open when the bike's on a rear stand. Vortex doesn't list one for the Duke and has so far been un-helpful, so I will have to figure that out on my own. I'm sure one will fit though. Oh, and I did break a couple things due to vibration: A fairing stay which I knew already had a stress fracture from bending, I can re-make that, and the exhaust hanger. I broke one at every race. I'll have to put some vibration isolation engineering into this. When I do the next round of upgrades I'll post a few more pix.

    Lastly, now that I know this really works and I'm having fun with it, it's time to sell off all my surplus brand-new OEM Duke parts. I will list those in the fleamarket as soon as I can get to it, probably in 3-4 weeks.
    #20