MO, for breaking in the drive belt, stay off the packed trail. Virgin lines where you can spin the track with the flip of the thumb seems to me will create the least shock loads the belt. You could combine this with the "Motoman" break-in theory in fresh snow by just being a little slower to full throttle and a little slower to release throttle (ease it on and off).
To me the most important thing is to let the belt cool while the production tolerances for tension are absorbed by the belt during break-in. From Poo's point of view, 100 miles is enough for the worst case scenario. MO is the fatter part of the Bell curve (most production units) will probably be okay to go in less miles (remember that's just my opinion).
If you break- in on a packed trail you will naturally tend to go off trail (got a deep snow machine right lol). As you leave the path and enter the snow you give it a squirt and spin the track up to 50mph then return to the trail and suddenly your track speed drops to 25mph as your track finds the traction. Then you do it again and again.
Even with light throttle, I believe these are exactly the kind of load spikes on the toothed belt you want to stay away from during break-in. Remember the belt wants to climb out of the top sprocket and until the unique Poo design gets a chance to form it`s "pockets" in the sprocket and belt teeth you need to stay away from sudden traction or HP changes.
It,s simple really and should not take a day of fun away. Just pretend you have a 500 fan the first day (if you can remember way back when LOL), then a 600 the second day, and finally, breaking in a sled the third day.
As for engine break-in, if your dealer or you let the engine idle for longer than it takes to just warm up, according to Motoman you've already lost your chance at the ultimate break-in.
Motoman's pictures are of a 4strk. I believe the oil added into the two stroke makes it a little different because the oil helps so much in ring seal and slight imperfections. Also ports come into the picture on every stroke. My experience has shown me that port chamfer is more important for ring seal than any kind of break-in.
Any kind of irregularity here and light throttle break-in over a longer period of time is best for the long run on your rings.
Again, IMO, if you have not disassembled your engines and compared wear, clearances and sealing with both theorys of break-in on a stock motor, you really don't know for sure. Just MO.
I have disassembled many, many motors after break-in. Being a racer-mech. on a small factory bike team back then, we built motors all winter. A dozen blue printed, hand assembled engines, a dozen extra sets of jugs and pistons and 1/2 a dozen cranks, for a 3 man team was just a start some years.
Everything needed to be run in and disassembled, inspected and either put into boxes for later or reassembled for first race.
Break-in. One of the riders was a old guy (lol young to me today) who learned his trade in Europe, one grew up on bikes, and me (a lucky rider). The old guy warmed up his tires- engine and took lines that kept his speed at less throttle, me I wheelied out of the pits and always needed brake rebuilds lol.
I got to tear-down these identical engines that were broken in in 3 different ways and never saw a difference in blow by or power on the dyno.
Just like everything in this world there is always an alternative point of view
