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KTM 520 EXC/MXC/SX Model differences

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I am on the hunt for a Dual Sport bike. I have owned 2 BIG XRs and was originally looking for an XR400 but realized that they were all old technology and still heavy compared to lots of other bikes out there. I then started going down the path of the WRs, but after researching the KTMs am sold. So I need some help understanding the different models of the 520sih range. FYI: I am looking for a bike to ride 90% of the time on the street, but that will be high performance in the dirt the rest of the time! I plan on running street slicks with a smaller sprocket (minus a link or two) for the road riding. Supermoto style minus the cool tricks I'll never be able to do :prof:

I understand the basics of the different bikes with regards to the tranny, unless you correct me! :lol: The MXC is the close ratio 6 spd, thje EXC is the wide ratio 6 spd (lower 1st and 2nd and higher 5th and 6th from what I've heard), and the SX is a close ratio 4 spd. I also have come to find out that parts can be swapped between the different models. i.e. gear swaps, and even adding 5th and 6th to the SX tranny, thank you KTM! :smirk:

I'm not sure of all the details but I know that there are suspension and perhaps engine/carb differences between the models. Anything in particular here? I assume that the SX engine is a bit more performance tuned than the others. Higher compression, etc. true? what about the MXC vs EXC?

My biggest area of concern is the dual sport-ability. I am looking at two MXCs tomorrow. One is a 2002 and is orange with black and has a headlight. the other is a 2001 and is orange with gray. are the different colors indication of slightly different models? Both have electric starts. The gray bike doesn't have a head light and the black does. I am hoping that the gray is still wired for a light. Maybe it won't matter when I pick up the aftermarket light kit.?

How about electronics? Are the stators different? Will I need to swap stators for the lighting kit? I read something about a mod on the existing stator? What about inter-model differences like an MXC that has an electric start vs a non-electric start?

There is a 520 SX that I am interested in getting and modding the tranny, stator, and adding the lighting kit. Seems like it would be a smoking bike but I am concerned that with the amount of miles I'll be putting on it I will be maintaining it all the time and rebuilding the top end frequently...

Oh and last but not least what should I look out for when test riding the bikes? I rode a 2006 tonight that was BEAT :lol: The whole body was dented and scratched, the kick start had huge gouges in it from hitting the foot pegs, the brakes were weak, it squeaked, burned a little oil of the head somewhere, and it sounded like either the piston was slapping around a bit or more likely the valves were really loose.

Anyway that's about all I can come up with for the time being. this is the 3rd time I've written this post because TT doesn't play nice if your away from your PC and get logged out and try to submit the thread :smirk: Anyhow, thanks for any help you can give me!

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Engines are the same apart from 450sx and the old 400 models which are totally different. Only difference between 450exc and 520/525 models is that 525/520 sx has conical (stronger) valve springs. Some year also has different cam, but that is rare. Sx crank is slightly ligher. All parts are ingerchangeable. SX has no stator for lightning, needs flywheel and stator. SX also has bigger carb and no tps sensor and different ecu. You will not want that for street use, very uncomfortable, feels more powerful but is not really. Nothing wring with bigger (41mm) carb, but no tps makes it very bad to ride apart from full throttle.

I'm not sure about the old models, but sx has adjustable preload forks and separate fast/slow speed compression adjustment which exc lacks. Forks itself are identical. Not sure about the mxc. Converting sx to 6 speed is 150€ for the parts. Not bad because it already has 6 gears on countershaft so only need to get two gears. Again, not sure about the old 520 models. It will be a mixed gearbox, but should be just fine.

REad this http://dirtbikesaction.com/topic/2465036/1/ more info at ktmtalk (evolution of rfs chassis and motor)

Also download rfs repair manual, google for 250-525 sm-mxc-exc repair manual pdf . Lots of info.

My opinion, get a 2005 or newer exc.

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Thanks for the info! The link about the engine updates was great.

I guess the SXs are off the list. Anyone have any info on some of my other questions? Electrical and chassis stuff between the MXC and EXC and differences between the same models?

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To make it easier on yourself and less expensive, you should consider only the 520 EXC model with the wide ratio 6 speed. The close ratio MXC tranny would be miserable for the uses you have in mind. If you want more gas tank capacity than the stock EXC 2.25 gal, there are a number of accessory tanks available or use the stock 3.4 gal MXC tank along with the MXC seat..

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For strictly street use mxc transmission is not bad. I have no experience with it though, but exc 1st is too short to be used onroad and 6th is tall enough. So a little taller first wouldn't hurt. But only if you know you will never be stuck in a tight spot. For strictly onroad supermoto use I would probably want something with closer ratio than exc, but in mixed use with sm/dirt wheels exc transmission is nothing short of perfect.

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I am not too worried about the MXC transmission because of the ease in changing the gears. I was thinking of putting in the higher 6th gear as an overdrive. I have heard mostly negatives on the low 1st of the EXC. But either way I can try different gear combos fairly easily. the MXC tranny will serve me better on the mountain! Also, even more important, I am going to run 2 sets of tires/rims. The street slicks will have a much smaller sprocket for ideal street use. I will most likely have to remove/add links...

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IMHO Unless you are in a hurry or find a fantastic deal, I would wait untill you come across a 2005 or newer 525.

why you ask,

Much better suspension, much better frame and internal motor upgrades compared to the older models.

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I may not be able to afford a bike that new that is still in good shape. the 06 I rode last night was up for $3000 but it was beat and anything in better shape would likely be much more. I really need to stay at around $2200 so I can still get the extra tires/rims and lighting kit, etc...

What would a good deal be on a 2001/2002 that is in good shape? would 2000-2200 fit in the good deal range or just average?

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Much better suspension, much better frame and internal motor upgrades compared to the older models.
Well, none of the changes were very critical, but still newer is better. Engine stayed the same from 2003 and even before changes were all mostly cosmetic, apart from carb which changed to gen II fcr in 2003 I think. After that small changes, 2003 came the new rear subframe and tank for sx, 2004 also to exc. CDI box changed 2005 to a better design and so on. I don't know about suspension, basic design stayed the same but valving definitely changed and then there are the preload and high/low speed damping adjusters, although I don't know if even the newest exc's have them?

Frame changed in 2005, measures and angles are the same, only material and looks are different.

One thing you should know, sx does not have a thermostat. It only costs 30€or something, but right side radiator lacks the return line so it's not a drop in thingy.

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I may not be able to afford a bike that new that is still in good shape. the 06 I rode last night was up for $3000 but it was beat and anything in better shape would likely be much more. I really need to stay at around $2200 so I can still get the extra tires/rims and lighting kit, etc...

What would a good deal be on a 2001/2002 that is in good shape? would 2000-2200 fit in the good deal range or just average?

It would seem high to me, but location plays a big part, also plated/not plated makes a difference.

I would expect to be able to find a 05 for around 2500 or less.

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Well, none of the changes were very critical, but still newer is better. Engine stayed the same from 2003 and even before changes were all mostly cosmetic, apart from carb which changed to gen II fcr in 2003 I think. After that small changes, 2003 came the new rear subframe and tank for sx, 2004 also to exc. CDI box changed 2005 to a better design and so on. I don't know about suspension, basic design stayed the same but valving definitely changed and then there are the preload and high/low speed damping adjusters, although I don't know if even the newest exc's have them?

Frame changed in 2005, measures and angles are the same, only material and looks are different.

One thing you should know, sx does not have a thermostat. It only costs 30€or something, but right side radiator lacks the return line so it's not a drop in thingy.

The crank got smaller lighter in 07, The cases got thicker in 06, clutch, torque limiter and valve guides changed in 05. lots of changes prior to 04

The 05-07 frame is considerably stiffer than the earlier versions -meaning it handles better.

The 03-04 forks have the much hated 3rd bushing, and the shock has the top out spring. nothing before 05 is considered good susp.

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The crank got smaller lighter in 07, The cases got thicker in 06, clutch, torque limiter and valve guides changed in 05. lots of changes prior to 04
Did all the cases get thicker or just those with 100mm cylinder? I don't think exc valve guides ever changed but that doesn't matter. My point is, engine is pretty much the same and no major changes were made.

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Yea, in Utah it's pretty slim picking. There's only been a total of 6 (3 are MXCs the rest as SXs) for sale in the last 4 weeks.

But they are still for sale:

2006 KTM 450SX - $3300

2001 KTM 520 MXC - $3100

KTM 520 with new 2003 KTM525 head - $2600

2002 KTM 520 MXC - $2500

ktm520 with 525 head just serviced. $2500

01 KTM 520 MXC - $2200

The 02 MXC that I am going to see tonight is supposed to be REAL low hours, as in it has sat most of its entire life. The owner just had the shop go through it all to get the carbs and gas cleaned out, and new battery, etc. If it is as good as it sounds and he takes 2200 I'll have a new bike today...

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Well, I did it. I bought the 2002 520 MXC foir 2350 (including a paddle tire and acerbis hand guards). It really has never been ridden. As in, the guy can count on one hand the times he took it out. Before posting it he had the local shop go though the bike and also replaced the battery. I figure that the minor differences aren't going to be that big of a deal for me. In fact I'm not even sure I would notice the difference on half of them, like some of you hardcore riders! Anyhow I'm stoked to have a good bike! Now I need to get the rest of my dual sport parts together and get her registered!

So back to the topic. My guess, after even more research, is that the MXC has the same stator as the EXC, at least in the early years on e-start bikes. To do a high beam lamp you can simply wire the stator in series? I am not sure if this removes the one of the circuits to accomplish this? I'll be calling trick tomorrow for some more info.

What size are the hubs/axles for the front and rear wheels on these bikes (i am of course interested in the 2002 model)? I'm probably going to buy some used stock wheels off Ebay and put slicks on them. Nothing fancy.

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Welcome to the ktm side of the world.

Like to see new people enjoying these.

You will need to gear up the bike depending on top speed needed for the street.

And regear the bike for tight dirt use.

The rear axle block that the adjusters push against flip over and are exactly two teeth different on the rear sprocket without re adjusting the chain or adding or removing links.

I use ironman steel sprockets in the rear and oem only in the front as the iron mans can be changed after being run and hardly wear.

No two teeth will not be enough.

The mxc trans is 77% gear spread in the box

The exc is 99%.

Exc 2 is roughly mxc #1 and mxc 6th is roughly exc 5th

The early head runs very well.

A bigger bore cylinder and piston is very helpful in the higher gears and for any higher altitude use.

Good luck

Doc bob

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I use ironman steel sprockets in the rear and oem only in the front as the iron mans can be changed after being run and hardly wear.

Bob, thanks for the reply. I was thinking of keeping the front 13T sprocket. I am not sure if it is OEM or not. I think all of the front sprockets are steel. After your comment I am planning on using steel on the rear sprockets as well. is there anything else to it? some special formula between the OEM front and Aftermarket steel rear? Also I will always use an O-Ring chain to keep stretch down to a minimum. My dad suggested have 2 different chains and 2 sets of sprockets while I am at it. Seems like it wouldnt be much harder to change it all out while I am in there swapping the rear tire/hub out and removing links from the chain...

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