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. 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. 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. 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. 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!