2005 KTM 525 MXC - Dirt Rider Magazine

I was so busy trying to rack up the final hours on my long-term KTM 525 MXC that I really hadn't considered how empty my garage would feel when it had gone home to KTM. It was not a good feeling to load it up for the final time. If the bike had felt worn out, I wouldn't be as sorry to see it go, but it still felt fresh and tight to the end. And that was in spite of a 24-hour race, a 24-hour ride, several days in Baja attempting to hang with Malcolm Smith, many motocross outings and dozens of abusive off-road rides. Some of which included mud and snow, and virtually all included some ugly hillclimbing. In all the years I've been at Dirt Rider, I've only had a few bikes that were set up specifically for my tastes and riding, and none have been as personalized to my riding style as this 525. Consequently, I was much less willing to loan out the bike to help the hours add up quickly. The bike felt comfortable, fresh and unbent, and I liked it that way.In the last 50 hours, and since the last update, I did perform some needed maintenance and repairs. The cam-chain tensioner had used up all the travel (a sign the cam chain is stretched), so I installed a new chain. KTM uses an endless chain, so I had to borrow a special tool and a flywheel puller, but otherwise it was an easy job. For the price of the two tools you could probably have a dealer do the work for you, though, since both tools are priced at a little over $200. Soon after, the rear brake master cylinder went out for the second time. KTM has upgraded the master cylinder, and the new ones aren't supposed to go out. Turns out the replacement came out of the press department's stocks, and it was one of the older units.The sole new modification was the installation of a $299.99 FMF Ti muffler with a spark arrestor. The stocker had gotten loud, and we could have repacked it, but Jesse Ziegler had one from his KTM 250 SX-F, so I slipped it on.The Dicks Racing suspension, Factory Effex graphics and even the 909 grips I installed at 50 hours are showing considerable wear but are still going strong. The budget-priced Rocky Mountain ATV Primary Drive brand chain and sprockets (installed at 100 hours) lasted 50 hours, so new ones were put on right after the last update. Rocky Mountain was sold out of aluminum sprockets (no doubt because they are a good buy), so I installed a steel rear for $18! The second set still looks pretty good.During the last 50 hours, the bike spent time in the desert and local mountains, but it racked up hours and miles at the Best in the Desert Nevada 200. Casey Folks and Scot Harden put on an incredible ride with an amazing variety of terrain. Probably the toughest conditions for the engine were the bottomless sandwashes. To help rack up hours, former National dirt tracker John Hateley took it fire-roading. Then some of the lads from work were looking for a mount for the Glen Helen 12-hour endurance race. That was enough time to finish out the 200 hours the bike needed with a little to spare. Unfortunately, the connecting rod bearing (big end) let go eight hours into the event. The engine never stopped running, but it began making ugly sounds and producing less power. At our 24-hour test, Thumper Racing's Gary Hazel said he thought the 525 engine was making too much noise and that the noise was crank related. His diagnosis was the reason I checked out the cam chain. The engine was quieter after the cam-chain replacement, so I thought the engine was fine. The postmortem showed that the bike had not starved for oil, and none of the parts were discolored from overheating. So apparently, the big-end bearing in the connecting rod simply wore out. Even though they were unrelated to the crank, the intake valves were dished, and they needed to be replaced as well. Some parts of the oil pump needed to be replaced, but if we had shut off the engine as soon as it started sounding unhappy, those parts probably wouldn't have been damaged. Before that fatal race, the last 50 hours had been relatively painless.Despite the connecting rod bearing failure, I feel completely comfortable recommending any of the KTM four-strokes. I believe they are the best four-strokes available for off-road riding. I suspect that my habit of attempting gigantic sand hills over and over again may have been partially responsible for the big-end failure. I don't know that 525s are supposed to get twisted that hard and long. The rest of the engine internals look ready for another 200 hours. I'd love to have the bike back for another 200, and I'm not the only one. Several of the riders who rode the bike during the Dirt Rider 24-hour test asked about buying it, even after they learned it broke! The bike was completely comfortable for me. Since I was trying to get hours on the 525, I haven't ridden off-road much on any other bike in over a year, but now that the test is over, I've had to go trail riding with other bikes. It has been a little frustrating to ride bikes that weren't set up for me and didn't work as well as the 525.Running TallyHours on Bike: 200-plusModifications: $299.99 ($2406.78 total for 200 hours)FMF Ti muffler: $299.99Maintenance and Repairs: $871.11 ($1907.38 total for 200 hours) (not including tires)Rocky Mountain ATV Primary Drive o-ring chain: $42.68Rocky Mountain ATV Primary Drive countershaft sprocket: $7.99Rocky Mountain ATV Primary Drive steel rear sprocket: $18.99Rear brake master cylinder: $149.79Cam chain: $54.34Crankshaft assembly: $473.862 Intake valves: $24.89 ea.3 K&N; oil filters: $6.14 ea.Nine oil changes with Maxima Maxum4 Premium oil: $6.14 qt.Adjust valves N/CDunlop D756 rear tire: $100.11Dunlop D742 front tire: $95.23Maxxis SI tires (2 sets): $70, front; $82.12, rearBridgestone M202 rear Tire: $85.69