I think I would be checking out driveshaft and jackshaft bearings. You can not grease them so I think they are a likely maintenance item. Chaincase oil change, grease the suspension, recharge shocks, set track tension(tight)...
Who did the motor? Polaris replacement? Shop built? Home built? Has it been set up and run by the engine builder/installer? With any new engine it is advised to run a cup of oil in the gas. This is so you can safely observe that the engine is using oil from the reservoir. If you don't know anything about the set-up, monitor the oil usage and calculate your ratio. You can adjust the oiler to around 30-40:1, and I would. At that point there isn't much reason to continue adding oil to the tank. These engines do not pass an fuel/oil mix over the bottom end bearings anymore. They are direct oiled so the oiler setting is your control over bottom end lubrication. It will run fine down to 20:1 so continue the oil in gas regimine until you get the oil pump set. I had my '13 at 30:1, ran great.
Otherwise there isn't really anything out of the ordinary on the sled.