16th Mar 2007, 00:03

I have a 2003 ktm 525 sx that works fine on the motocross track. Once you take it for hard enduro riding, all sort of problems start. Once it blew the water pump seals, and another time the rubber grommet that holds the stator wires popped out and I lost all oil. I can't understand why it happened, was it because it got hot and built a lot of pressure? Has anyone had a similar problem?

14th Apr 2007, 19:59

I just bought a brand new 06 KTM 525 SX. I have ridden it three times.

I stalled it in a mud hole full of water just under the foot pegs. When I kicked on it to restart it, it sucked water into the crankcase vent tube and filled the crankcase with muddy water. Needless to say it ruined the engine.

When I took it to KTM, they informed me that the bike had a 30 day warranty, and was no longer under warranty.

I've noticed all the 07 bikes have the vent tube routed up the air box instead of under the engine. Any one who has one of these, I recommend rerouting the the poorly located vent tube and save your bike from imminent failure.

18th Apr 2007, 01:48

That does seem a bad fault with the bike, however I've seen quite a few motox bikes that have this design.

Maybe you should have pulled it out first?

27th Jun 2007, 05:45

I've had my KTM 525 since 2005, it's a 2004 model. It's not had any problems except the stand broke off and the oil screen plug got chewed up once. Other than that, it's been fine. I've just done the servicing as and when, and it's behaved perfectly.

Sounds like you had a run of bad luck matey. These bikes are the nuts as far as I've seen.

6th Aug 2007, 11:58

WARNING: Do not buy a KTM if you don't know the first thing about turning a spanner!

KTM's are definitely "race" ready.

They are a race machine; you don't buy an F1 car for fetching the shopping and expect it to run for 10,000 miles without an oil change. It's the same thing!

Unless to have a deeper wallet that Richard Branson, or your name is David Knight, servicing by a dealer is not an option, so get yourself a decent socket set and expect to have to use it!

11th Aug 2007, 22:23

I have a 2007 525 EXC and the bike has never had a single problem. I have always turned my own wrench; it's the only way to get the job done right the first time.

2nd Sep 2007, 20:51

My father and brother both have 525 EXC's - they are great on trails, woods and open areas. However, at 14,000 feet in Colorado I have seen numerous problems. My father had a lot of trouble with overheating as well as my brother. Leaking antifreeze out of the caps. My brother's bike broke the bolts on the top of motor and lost a lot of oil, and had them replaced with "factory upgraded ones." Well the next year my father had the same problem and had the same solution.

Again, this year my brother's bike snapped the bolts again - well it did make one trip. OK, bad luck - for them both - money is no problem - it's the riding that's impossible.

My Honda has made the trip 8 years now, no trouble. They're just high maintenance bikes; really high maintenance at almost 15,000 feet.

12th Nov 2007, 21:12

I own an 07 525exc. De-restrict the pipe and re-jet for overheating issues, other than that this bike runs great!

Change the oil, filters every third drain/fill and valve checks every third oil change and waallaaww! You've got a damn reliable DS!

I'm surprised at those motor failures, KTM is an outstanding company and for the most part these are very reliable motors!

15th Mar 2008, 05:04

I have an 06 525 EXC and can relate to the boil over issues, but only during slow technical riding when obviously there is no air flow.

Solution: get the 95.00 bolt on cooling fan (KTM accessory). Your EXC has all the connectors built in to factory wiring harness and it comes with thermostat, so the fan only comes on when needed. The only drawback is battery life suffers, but it's well worth the extended engine life and no hot anti-freeze on my riding pants! I'm approching 2500 mean AZ desert miles with an occasional 8k high riding weekend thrown in and have had 0 mechanical failure.

Change the oil every 2-400 miles and adjust the valves every 20-30 hours, and I couldn't be happier with this bike!

22nd Apr 2008, 21:50

I got a new 2007 KTM 450 EXC Dual Sport. Bought in Jan 08 off the showroom floor.

First changed the jetting before I ever rode it. Somehow pinched that magical vent line, and vapor locked the motor, blew the head gasket, and the dealer took care of it.

I did the exhaust mod, and it really rips now.

Oil was never changed when they rebuilt my top end, and the gas tank was empty on return of the bike. Changed the oil on my own, rode the bike once, runs good, no overheating issues.

A buddy of mine rode it tonight and held it wide open at least for 15 minutes, ran the brains out of it. No problems so far I guess.

Magneto side of motor gasket torn and coming out from under the side cover. What the heck, did the dealer do in there other than ruin some gaskets? On my oil change I found pieces of gasket in the bottom of motor screen / drain plug!

12th Jul 2008, 07:33

I have a 2007 525 outlaw, was driving it the other day and in 5th it just quit. When I restarted it it has a rapping noise. I have checked valves and clutch everything looks good. Can someone please help?

7th Aug 2008, 17:49

I recently bought an 06 KTM EC 450 used. The front brake blew out on my first ride. I rebuilt the front master cylinder for 33.00 and it runs like a champ. I couldn't be happier!

2nd Sep 2008, 14:27

I have also bought a 525 SX 2006 bike after 30 years' break of driving motocross. I have regularly changed oil and filters. Now there is a quite heavy noise coming from cylinder. Do you have any similar experiences? Could it be cooling or something else? Would have expected that for a senior driver, the motor would have lasted longer time.

17th Oct 2008, 05:57

Sounds like a lot of you have bad views on the bike. I race enduro and have sunk my bike up to its handle bars, all I had to do was change the fuel, oil and clean the carbie, and it was off and running again.

Maybe some of you should learn how to do some of your own work and maintain your bike, and you might not have so many probs...

The bike goes hard, and given respect and care (maintenance) will do so for years...

Jezza, NSW.

4th Dec 2008, 21:23

I have a 2001 KTM 520 EXC. The magazines went absolutely nuts over it in 2000, the first year. I could not get one until 2001.

I have quite a history with this bike. I agree with other comments about learning to work on your own bike. First off there is a certain gratification knowing that you fixed the problem and fixed it right!

I have one way to sum up the KTM racing series four stroke motorcycles. They are the Maico of the 2000's. Some of you younger riders may not know the history of Maicos, but they were the s**t in the 70's up until the last good one, the legendary Maico 490.

KTM racing series four strokes are purebred racing bikes that need racing bike maintenance, just like Maicos did back in the day. I own and race both Maico in post vintage AHRMA and do AMA dual sport and an occasional hare scramble, and a lot of trail riding on the KTM. It is now a 570 beast with porting by Thumper Racing and a DOMA full racing header. Nothing keeps up with this bike in 5th or 6th gear, and yes I have raced Honda CR 500s, Husaberg 650's, modified Honda CR 450's, Vertamatis, you name it. If I was beat it was because my skill level was the problem.

If you want bullet proof reliability, buy a Honda XR and keep it bone stock. If you want to go fast, buy a KTM and put away a few bucks for parts and learn to wrench. Go to any AMA national hare scramble or enduro and count the KTM'S there is a reason for that.

I have had several mechanical failures with my bike, and yes they do overheat easily. Also I have had several seal failures along the way. But all in all, being a racer and at 50 yrs old, having had over 60 motorcycles, my advice is think about what you want out of your motorcycle, do your homework, don't buy on impulse, and by all means get some good maintenance reading material. Talk to to other motorcyclists about their experiences with their bikes and different brands they have owned, and buy some good metric wrenches. Do your home work and make your choice. There are many terrific motorcycles out there. KTMS are race bikes, they need race maintenance!


12th Sep 2010, 22:56

All you guys complaining about overheating, there is a simple solution!! Buy a coolant overflow reservoir from Motion Pro for 25 bucks, add engine ice coolant and the problem is solved in 30 minutes!!! Use a little proactive thinking and your bikes won't boil over!!

My 06 525 EXC is the most reliable off road bike I've ever owned, and turning your own wrenches, you always know what's been done to your bike. Check out a great resource at ktmtalk.com, to gain some knowledge.

2nd Feb 2011, 06:59

I have a lot of problems since I bought my KTM EXC 450 2003... Can I change my engine to a new model? If yes, which model?

11th Feb 2011, 17:33

Yeah Babe.

XR400r never has let me down. Not on Troll trail nor Kill Trail. Not on any Enduro I have ever raced. And yes, as technical as you can get yourself into. Thump, Thump, Thump.

1st Jul 2012, 20:06

I have a 06 450 SX. Just rode slow trails. White smoke from the exhaust and a gurgle sound from crank case breather tube upon a slow kick. Other than that, it rips.

6th Jul 2016, 22:22

I have a 2003 450 EXC that I've flogged the crap out of from new. Raced motorcross, enduro and dirt track on it, and got 54000 km on it before I rebuilt it. I've been a bit over the top with my maintenance, but it is obviously worth my efforts.