I own and operate an XP 154 and was surprised that what you guys are describing happened to me also, so I spent the rest of the winter assessing the situation and heres is my conclusion:
THE SUSPENSION IS NOT THE CULPRIT; ITS THE SECONDARY CLUTCH!!
THE ISSUE:
When you go to sidehill, you hit the throttle to take pressure off the skis to lay the sled over at the same time that you are pulling on the bars to complete the movement. This sudden acceleration of the secondary clutch amplifies the gyro effect and "snaps" the sled back to its original skis-down-position. (this usually tries throwing you off the outside or gouging your ribs into the bar end). If you lay the sled all the way over and then gas it, it seems to want to hold that position until you get stuck on your side. Frustrating, isnt it?!
MY CONCLUSION:
The XP design has the highest secondary clutch on the market. This clutch is spinning when you lay the sled over to sidehill. This spinning action of the clutch acts like a large gyro whose effect is far greater than other designs because of the high clutch placement (versus say an M-series sled).
THE FIX:
It took me awhile to master but heres what you can do. When you throw the sled over to sidehill, try not to gas it until it is at least halfway on its side. Then, give it a little gas and let off and pull it over to the desired position. Then, give it hell and it will keep the sidehill position like a dream.
This technique fools the gyrating effects enough to allow you to predictably handle sidehilling maneuvers.
I know Im no expert on the subject but I hope this helps!
