With the Outlander 450, I have found that the #1 issue is premature belt failure. The belts only last about 2000 miles for the serious rider before the belt shows signs of cracking or completely fails. It is absolutely essential that when a belt is in need of replacement, you properly service your CVT. Remove the left side body panel, left side step well, and the CVT cover. Use the belt removal tool or your own fabricated tool to get what is left of the belt off. Use an impact driver to remove the primary (front) clutch bolt and secondary (rear) clutch bolt. Remember that they are spring loaded so hold onto them so they don't fly off. Also remember that the primary clutch is reverse thread. Then remove the primary clutch spider and outer sheave as an assembly. Mark with a file part of the spider and sheave so when you separate the two, you don't put it back together differently. Remove the spring and ring behind the sheave on the primary shaft. Then carefully remove the 1 way clutch, making sure to put your fingers over the 2 pins/springs to keep them from flying out, never to be found again. Insert the special tool into the primary shaft to remove the inner primary sheave/flywheel. Remove the plastic starter drive gear cap and starter drive gear. Take care not to lose the spring and washer inside the plastic cap. Remove the secondary clutch sheaves and then the spring, then the shaft, the plastic cam, then the metal star piece. Remove the metal plate that looks like a casket. It covers the selector position wires I believe.
Now clean everything. Vacuum the CVT inlet/outlets and the inside of the cvt. Make sure the sheaves are free of black belt marks. Rub from center to outer edges on the sheaves with a scotchbrite pad to score the surfaces. I use brake cleaner for the cleaning. You will go through 2 cans if you had a complete belt failure. Look at the primary clutch governor cup (spider) and look at the ramps, rollers, and shoes. The rollers may have flat spots. Replace all rollers/shoes if this is the case. Check ramps for excessive lateral wobble. Check the primary spring height compared to the manual specs. Check the pins and springs from the 1 way to ensure they are in specs too. Remove the 1 way clutch bearings and the dust covers for them. Clean the bearing out of all grease and then repack with isoflex grease (expensive). Replace only one dust cover and leave the other side open. Have the open sides facing inward on the clutch when reassembling. Ensure that the bearing race surfaces are clean of grease so they don't spin in the housing instead of working as a bearing. Grease the center of the clutch where the pins slide on. Grease the pins before reassembly as well. For the secondary, remove and clean/grease the bearing on the outer sheave just like you did for the 1 way bearing. Remove the plastic piece inside the secondary and clean in there as well. Check the said plastic piece and the cam for damage. Lightly grease the inside of the secondary shaft for assembly. Check the secondary clutch spring against the specs in the manual. Brake clean spray the starter drive and cap but do not lube the starter drive. It wouldn't hurt to grease the ends of the starter drive. Clean and lightly grease the needle bearing inside where the starter drive goes. Okay! Reassemble and torque the primary and secondary bolts to spec. Ensure the belt arrows point clockwise. You should be good to go! Oh, be careful with the CVT case bolts. You barely have to tighten them, otherwise you will strip out the threaded inserts.
Preventing premature failures hinges on proper servicing of the CVT, so at every service interval, open the CVT and clean. If the belt is glazed, cracked, etc... then replace it. It is well worth it to avoid the mess a complete failure makes!