Boring KTM Rebuild Thread

[El Camexican]

Exactly what the title says. There is nothing special about this rebuild, but due to some comments made in another thread I am going to try and do my part for the forum and post a benign, non-controversial thread about wrenching on a bike.

The backstory is that this was once my spare bike that was set up for single track riding, but was recently outfitted with a desert tank, headlight and some suspension changes to allow a buddy that came down to accompany me on a two day off-road adventure.

Unfortunately, as skilled a rider as he is, the bike suffered from some gravitational intervention and fell down about a dozen times, two of which were pretty serious. One of them so forceful that it pulled the pipe off of the cylinder and we had to bend it back onto the spigot using a combination of tow straps and dead fall lumber.

I’ve had a freshly Powder Coated frame sitting in my loft for a few years now, so I decided that rather than just patch together the bike with some repairs, I will give it a complete makeover and then later on refurbish the grey frame which is probably the best one I have of the four and use it on my regular bike which I suspect is tweaked at the swing-arm mounts.

So here begins the boring pictorial history of swapping parts from one frame to another, enjoy

[El Camexican]

Step one is to always clean the vehicle before starting, so given that that was done a few weeks ago we can skip directly to step two which is to grab up a bunch of plastic bags and sharpie to put hardware in and label and a pad and pen to note any parts that will need to be purchased and replaced.



I told you this was going to be boring!

[El Camexican]

In these photos we can see the extent to which the pipe was bent. Needless to say I have no intention of trying to fix this and have sent the bill to my buddy for a brand spanking new Pro Circuit unit.

[El Camexican]

Whoa Nelly! (As my grade 6 math teacher who had horse named Nelly would say) seems we’ve encountered an engineering deficiency!

The plastic spacers meant to hold the aftermarket radiator guards in place seem to have failed due to the heat generated just above the engine. This causes the radiator guards to wiggle around a bit which in turn causes the tank to be loose as it is connected to the radiators via the shrouds.



The fix is to replace the melted plastic with potable water grade Mexican PVC pipe. Note the ultra accurate tenths of an inch tape measure complete with .020” increments. This is the ultimate tape measure for screwing with your know-it-all friends heads.



No time like the present to take care of these little details so that the reassembly process can be relatively smooth. After carefully marking and cutting the pieces they are deburred with an array of specialized files and then cleaned with solvent to remove evidence of their original purpose before being tested for fit and function.



Talk about bling!!!

[El Camexican]

Seems on one of my friend’s spills he gave the rad a little bump. Easily straightened, but having had a rad crack on me a few years back in the middle of nowhere I prefer they not be stressed.



Now here’s a little part worth mentioning. I installed this a while back to satisfy my curiosity about what temperatures my engine was getting to. Turns out that unless I am moving along at over 20 miles an hour my engine is constantly in the red zone. I think I liked it better when I didn’t know how hot my engine was.

[El Camexican]

Seems neither the upper or lower chain guide rollers survived this trip. I’ve worn a few out before, but I’ve never had one fail and fall apart like this let alone both.





You don’t have to live in Mexico or own a KTM for much time to realize that if you don’t want to interrupt your riding plans you better have a full assortment of spare parts on hand at all times.

[El Camexican]

Seems the motorcycle Gods have thrown up another roadblock on our path to completing this project.

I noticed that the kick starter squeaked and seemed a little stiff when I went to remove it from the engine.

The culprit was this broken O-ring which allowed dirt and water to get into the mechanism.



After a thorough cleaning the O-ring was replaced and the assembly was given a healthy coat of grease, particularly in the spring and ball housing.



Before you guys fill up my PM box asking what kind of grease I recommend for this task, let me tell you that it is Timken brand. I swear by this grease and will continue to use it until I runout. After that I will go back to Autozone and buy the cheapest grease they have and will swear by it until I runout again. Guess you could say I’m brand loyal to the end.



Once again having spares on hand saves the day.

[El Camexican]

Now comes the critical moment when you remember that your swingarm bolt passes through your engine cases and therefore when you go to remove the engine your frame and front end will be left balancing on your stand at the mercy of the same gravity that necessitated this rebuild in the first place.

It is at that moment that you think back to all the times your so-called friends came over for help on their bikes and in return promised to come over anytime you needed a hand and then you remember that not one of them has the testicular fortitude to tell their wives that they would rather come over and help a friend with his bike than rub their feet all Sunday afternoon on the couch and you tell yourself for the hundredth time that that you’ll never help these sad fuks out again.

[El Camexican]

Once you come to grips with the fact that you are going to have to do this alone, it is always recommended that you loosen any hardware that you will eventually have to take off in a less convenient position, like with your frame laying sideways on the floor.


In this instance I will be removing the low profile retaining nut on the top of the triple tree so that I can pull the bars off before I remove the engine.




The key to not damaging a low profile nut or bolt is to just leave it alone, but if you must remove it use a socket which has been ground flat to remove the taper that normally exists to facilitate placing a socket over the head and clearing the slight radius where the hex meets the head on a normal nut.

[El Camexican]

.... and then your wife comes down to the shop and asks what it is you’re doing that is preventing you from being upstairs and rubbing her feet and it occurs to you that a foot rub might be a small price to pay for asking her to hold onto the front end of the bike for a couple of minutes while you’re taking the whole thing apart.

This concludes our progress for today. Please stay tuned for more exciting updates as the week progresses.

[Red Rider]

Looking good EC. I'm learning a lot. Not only on tearing down a motorcycle, but also on relationships & friendships. In the last pic, I see your KTM 3-wheeler, so I wonder how goes the progress on that?

[El Camexican]

Looking good EC. I'm learning a lot. Not only on tearing down a motorcycle, but also on relationships & friendships. In the last pic, I see your KTM 3-wheeler, so I wonder how goes the progress on that?

I’m flattered that someone with your skills would learn anything from my drivel. As far as relationships with friends go, there are at least a dozen people on here I’d trade for my current neighbors (I’m sure my neighbors feel the same way about me) and a few of my mechanically inept friends.

Life got in the way of progress on the trike about two months ago, but I intend to get back on it as soon as this bike nonsense is over. One of my biggest issues is still that darn air intake system. The more I look at it more I’m convinced that a pod filter on the carb is the only way this works.

I thought I had it figured out with that weird looking steel snorkel, but there is no room left for hardware to attach it to the plastic airbox on the fenders. This means that I would have to build a new one and reduce the size of the opening, specifically the width and that would mean that the square inches of opening on the rectangular section would be less than the square area of carb throat. I’m no engineer, but I’m pretty sure that equates to a bottleneck that would severely hampered the performance of the trike. I’ll post more details on the trike thread when I get back to it.

By the way, if anybody is having issues with my attempted tongue in cheek witticisms in these posts, try reading them in Phil Hartman’s voice as though he was narrating an informational film on the Simpsons circa “if a cow could eat you it would”

[Red Rider]

I’m flattered that someone with your skills would learn anything from my drivel.

Thanks for the compliment. It's always nice to see others' techniques, so I can pick & choose the techniques that I like, and add them to my skill-set. For instance, your "low-profile nut technique" is a good idea. I never would have thought about grinding down the socket, to give it more contact area on the nut, thus reducing the chances of boogering the nut up. Brilliant sir, just brilliant!

Life got in the way of progress on the trike about two months ago, but I intend to get back on it as soon as this bike nonsense is over. One of my biggest issues is still that darn air intake system. The more I look at it more I’m convinced that a pod filter on the carb is the only way this works.

Once again, I'm sorry about the extra work involved in trying to make the airbox work. I kind of feel responsible for that one. Whooopsie! I just hate to see pod filters on good looking builds, but if that's the only way it will work properly, then there is no other choice.

I thought I had it figured out with that weird looking steel snorkel, but there is no room left for hardware to attach it to the plastic airbox on the fenders. This means that I would have to build a new one and reduce the size of the opening, specifically the width and that would mean that the square inches of opening on the rectangular section would be less than the square area of carb throat. I’m no engineer, but I’m pretty sure that equates to a bottleneck that would severely hampered the performance of the trike. I’ll post more details on the trike thread when I get back to it.

I agree. There's no use in building the snorkel, if it's going to strangle the motor, and hamper performance.

By the way, if anybody is having issues with my attempted tongue in cheek witticisms in these posts, try reading them in Phil Hartman’s voice as though he was narrating an informational film on the Simpsons circa “if a cow could eat you it would”

I understood what your intent was, and I must say, it's a refreshing change from most of the threads here lately. The build threads, on the performance/sport trikes, have always been my favorite, but they've become few and far between here lately. I must admit, I was imagining the wrong voice while reading this thread. I could clearly hear Ben Stein's monotone voice as the teacher, on The Wonder Years. And strangely enough, that voice works quite well as the narrator.

[yaegerb]

Once you come to grips with the fact that you are going to have to do this alone, it is always recommended that you loosen any hardware that you will eventually have to take off in a less convenient position, like with your frame laying sideways on the floor.


In this instance I will be removing the low profile retaining nut on the top of the triple tree so that I can pull the bars off befor I remove the engine.




The key to not damaging a low profile nut or bolt is to just leave it alone, but if you must remove it use a socket which has been ground flat to remove the taper that normally exists to facilitate placing a socket over the head and clearing the slight radius where the hex meets the head on a normal nut.

Very cool tip. I just learned something new!

[El Camexican]

I must admit, I was imagining the wrong voice while reading this thread. I could clearly hear Ben Stein's monotone voice as the teacher, on The Wonder Years. And strangely enough, that voice works quite well as the narrator.

LMFAO! That works too LOL

I forget exactly where I learned that socket trick, but I think it was on a fork disassembly video. Now I have a bunch of them. KTM’s have a lot of low profile aluminum hardware and it’s not hard to damage them.

As far as some of the goofy detail in this thread, I’m one of what must be thousands of people that feel cheated when watching a show like American Chopper, or Overhauling and see them jump from start to finish with no one busting a knuckle. I’d rather watch someone wet sand a paint job than stare at a completed subwoofer box.