Here is some pictures of the mods and thoughts I did to my 640:
I got my 640 the 18th of May 2006 (same year model) and 11 months later it has 24,000 miles (25,000 next week...).
As everything and especially bikes (any motor driven vehicle in fact) it had a few problems but nothing that will push me to a new bike or an other brand.
After the first 600 miles I changed the final gearing to 16:45 (original 16:42). This is a worth while improvement and at the next service I will even go to 16:47 as I am now running permanently the Michelin Desert (front and rear) and the rear tire is ...big.
The original exhaust was changed for an Akrapovic slip-on. The air box was modified as well. But from day one I was not 100% happy with the carburetor settings. In Johannesburg we are at 6000 feet, so I was going by the KTM dealer settings... To cut a long story short it took several month (yes!) before I could get what I wanted. The engine now pulls hard and has a lot of guts at the bottom end. The settings are pretty much the "standards" for a LC 4 (Creeper) but I increased as well the idle jetting and got rid of a lot of popping at deceleration plus a crisper response around 3000 RPM.
I got the "crash bars" (H&P) but even with the new rubber mounts I had to re-weld them so many times that one day after one broke for the #*%$ time I just put them to rest along a fence. Funny: some vibrations disappeared after that...???
As I am 6' with looooong legs, I fitted a bar raiser. Not too tall as the control cables are pretty short...
A fuel filter was added as gas can be a bit dirty here in Africa if one travels to the remote areas.
The aluminium bash plate was swapped for the plastic one. It is quieter and goes more around the engine. I feel this is a better protection. Granted I do not race MX or do a lot of rock climbing...
The forks are protected with the neoprene sleeves. Unfortunately the clearance between the plastic stone guards and the tubes is such that these sleeves have to be replaced every 5,000 miles as they are worn by the friction against the plastic guards. I never had an oil leak and replaced the fork seals a couple of time by precaution as they were still in good shape.
The side stand is a different story. It took a bit of designing and fiddling to get it working the way I wanted. First the dual spring story... Have you ever played with a crossbow???!!! You got my drift. So, I only use the smaller one. Secondly, the way it is designed it doesn't stay extended. Great for the greenhorns forgetting their stand at pull-off but in the soft stuff I had the thing "collapsing" under the weight of the bike a few times. So, with the use of a grinder the cut out was increased until the stand stays put when extended. Great, but now the bike is leaning to much... so, the tube was extended by 1'1/4 between the elbow and the end. Lastly, the way the stand is mounted puts a lot of pressure on the central stand bolt. By the way, as most of you know, this a very strange design in this area... and this is a pretty weak point as well. The KTM bolt was taken off and a "good size" one was welded. The down part of doing so is that you can't tighten the nut too much or you will get everything locked solid... I used a self locking nut used on Russian helicopters: it resists all the vibrations you can trow at it. The side stand mount moves a (very slight) bit but you really have to use force to do so and it has never given me trouble.
The tool box is one of the two things I am proud of. It is a riveted aluminium tube with two caps. One is riveted and the other one is secured with two aircraft spring locked latches. The aluminium bracket is riveted and the whole contraption is treated to T4 (for the specialists) what makes this grade of aluminium particularly stiff and resilient. Yes, I know, it is nice to work with the aeronautical industry and have some guys making the stuff you dreamed during your weekend ride. Back on the tool box: a steel plate of 1/16th was welded on the rear frame (like on the exhaust side) to strengthen and stiffened it. See pictures for the final assy.
The GPS bracket is the other little "thing" I am proud of. Picture is self explanatory. It is bolted on the dash, not much room there and the electrical connection is done trough one of the existing empty connector. The Touratech mount is just a handle bar mount without the handle bar adaptor. Simple, straight forward and the GPS is just where it needs to be and level with the other instruments.
Now another piece of interest: my "top case" attachment! First, the aluminium plate is riveted to the cargo rack. It is NOT pop riveted but Cherry Max (aircraft quality pop rivets) are used. Yes they are very expensive but they have a stainless steel shaft and can take (a lot of) vibrations.
As you can see the plate has its sides bend. Here is why:
Now for the Pelican box I just fitted steel rods (1/4') trough the reinforcing ribs as you can see on the pictures.
The nylon straps with the strong metal buckles finish the trick. Easy to mount/remove, very durable and sturdy and you have access to your stuff without having to untie everything...!!!
I changed the original hand guards for the Acerbis ones after breaking the clutch lever. Very sturdy and excellent for the single tracks here with all the (big) thorn bushes too close for company. The down side is the increase in vibrations in the bars...
Last thing is the extension lip on the front fairing. It does improve wind protection but increases the buffeting.
Now, for the problems I ran into along this (almost) year and the many miles. As I said in my report on my last trip, the bike was serviced by the book every 5000 km (a bit over 3000 miles) and oil was changed in between. KTM has now a world wide data base per bike and they can track if the service has been done properly, when and by whom. It sure must help in case of warranty claims...
I had a slight oil sipping at the right cover (alternator side) that took a long time to get sorted out. Probably one of these machining problems.
The first real issue was a blown lower gasket, changed under warranty. Luckily this happened just 20 miles out of home on my way back from a weekend adventure... The bike was "only" 12,000 miles old. The problem was that the engine was mounted with a paper type gasket. It was replaced by a metal one, now standard on the newer models.
The top button on the trip master packed off at 10,000 miles and the whole unit was replaced, again under warranty... It is starting to act again and, this time, I had a look at it and understand the problem: it is a little white plastic plunger that pushes the switch. This plunger is "clipped" on the switch it self but with vibrations and wear the clipping forces are not as positive and eventually it moves away from the switch. I think that by using a spacer between the plunger and the rubber button on the cover will prevent the plunger to move away. I still have to experiment with this.
After complaining about some "little noise" a couple of time, the mechanic finally looked closely and found the the stator to have come loose and broke the attaching lugs from the cover.... Got it on time and no damage was done to the engine. The clutch basket in the process got slightly damaged and it was decided to change the whole clutch and disks. Once again under warranty except for the discs. But I basically got a new clutch for free at 20,000 miles! Apparently, the 3 retaining bolts for the stator were not locktighted and came loose under the vibrations and then, when the play got too big, broke the lugs.
The bike has never let me stranded but I was lucky (see above!). This could happen to any bike in any case. Where I have a problem is more with the dealer(s). They have a tendency to do things on the "cheap" side. I can understand that not everyone is ready to pay for the regular "full" service each time. But if asked so, they should do it gladly (more $$ for them). The other very big grippe I have is with their spares... for the clutch change they had to strip of a brand new bike.... I am speaking not of a "regular" official KTM dealer here, but about the South African importer...
They sold the 640 big time and some parts that are called for regular change in the owner manual are not even in stock (some have never been)!
As I said one time very loudly in the dealership as I was really pissed off: the KTM bikes are exceptionally good, but the dealership(s) give them bad reputation...
Now, on an other subject... I went trough 5 front rim... the last one seems to do better (new KTM front rim and a softer setting). Tire wise I have tried a lot of different ones: the best are the Michelin Desert (for me). I did ride under pouring rain yesterday and yes, you have to be cautious (understatement!!!). I used 15 rear tires and 11 front, one front exploded on a rock and two rears got bad punctures.
That's all... I am sure I forgot some stuff but this is what I remember most.