Why? Why: I have (had?) a 2006 KTM 640 Adventure. I like the bike's concept but I think KTM missed the mark on a few things. The good parts of the 640 ADV: Carburetor: you can fix it trailside and it needs no battery to run 7.1 gallon tank: you only run out of fuel if you spring a leak Dual disk front end: if one gets damaged, you can remove it and still ride. Until that happens, the bike stops NOW and doesn't wear through pads quickly doing so Really nice suspension: The fork does its job well without any love from me except yearly oil changes. The rear shock is rebuildable and gets love every two years. 520 chain: I don't know who speced a 525 chain on a DR650 but they ought to be shot. You can find 520 chain in a decent hardware store, a 525 isn't in stock in large moto dealerships. Kick start: you aren't having an adventure until your battery goes flat. Be it from waking up to ice on the ground and your battery is too cold to get out of bed or maybe from sucking water at a crossing that is just a bit deeper than a good idea, all the good rides require a kick starter at some point. I got good at push starting a DR650 on loose surfaces but enough is enough. Cush drive: if you like your engine, damp out the feedback. Honestly most of my riding is commuting. Pavement and no cush drive leads to chewed up output shafts. Even honda 90's have cush drive, why is this a debate for a bike with a license plate? The bad parts about the 640 ADV: The LC4 engine: it shakes like a paint shaker. I used to think people were being whiney bastards when they complained about this but it turns out, this is bad for the engine too. The shaking causes all the o-rings on the bike to fatigue. Buna N o-rings last about 5,000 miles and Viton last about 7,000. After that, the o-ring leaks. This is fine if you don't mind a drop or two of oil all over your everything but the real problem is the clutch slave cylinder seal fails like clockwork. I changed that o-ring with every oil change and still worried I'd loose my clutch. The engine also apparently has a habit of eating the intake lifter... yah... I got the memo late on that one. BST40 carburetor: I get that the bike needs to pass emissions but... yah... The low fender was gone on mine before I got it. You still need at least a little battery for the bike to run. The CDI box is attached to the main circuit so a completely dead battery is an issue as far as getting a spark. I have read that disconnecting the headlight lightbulb would allow the bike to fire off but despite kickstarting the bike more than electric starting it, I could never kick it over with a completely dead battery. Things that annoy me about the bike: The rally fairing: I get it, some people are wanna-be Dakar riders. And some people ride their offroad bikes on the highway only. But my happy place is knee deep in a water crossing or on single track that hasn't been ridden yet this year. I want visibility and the fairing is in the way. The headlights: These things look cool but don't work for anything. They are body mounted rather than fork mounted so they work better for going straight but don't work well for turning in the dark. They are brighter than stock DR650 lights but still not good. So short list of shortcomings with the KTM but replacing the engine is not something that one does on a whim. even with the obnoxious O-ring issue, I had grand plans to follow the ridiculous maintenance schedule this bike demands and keep riding the bike as it was. If I had known about the likelyhood and sevarity of the intake lifter problem, I'd have replaced it as preventative maintenance. In fact, I had just done the water pump about 500 miles prior to engine failure. However, Once the engine ate its self, I felt like I had finally exhaled after holding my breath for 6 months. This is an opportunity to banish that LC4 and I intend to seize it.