Put over 5k miles on an 04 800X 144, bought new, and half of them stock.
Running weak points stock are the skis and the 'flying nun' front clip. There are braces available for the nun if this sled doesn't have them - highly recommended if you are going to take it offtrail. One hard hit to a ski can bend up the front (you'll see the ski pushed back and inch or so). Too many guys found out the hard way. Braces were readily available for the 440x race sled, riveted in, and worked great. If you ride offtrail, you've been warned. Sled really liked simmons skis, the stocker offsets, those were garbage.
This was also the first motor with isoflex grease on the main bearings (they were sealed and not lubed by oil injection). Some lost crank bearings, particularly PTOs, and would also tend to push out the PTO seal behind the primary, doing nothing good for the bearing. FWIW.
Other than keeping the clutches clean and aligned, carbs clean, the sled is a workhorse fun machine. The stock 2" track is really good all around, and tough, but obviously only a 2" 144 - it won't climb or push pow like a bigger track. The stock TRA will wear out bushings ridden hard, doing nothing good for clutching. Just life with the TRAIII. Watch out for the Y-pipe allen screws backing out of the cylinders - can easily be fixed with norlock washers. I did many mods to the sled, just because I could, but stock, they were fun, high performing, and pretty reliable.
