So the when you dismount the motorcycle it remains on the table as S4 1STR token. Do you treat it as an obstacle? Can you move through it? Do you need to stop entering BtB contact?
Over time we have tested many things with motorcycles... even that a motorcycle without a pilot can be used, or stolen, by any other troop. In N4, to accompany the simplification and reduction of rules, what we do is once the pilot dismounts, consider it a scenery element with S4; come into contact with it does not stop the movement, but it does provide partial cover.
It definitely doesn't provide partial cover. There's no rule that turns a token into a scenery element. Whether it stops movement: the relevant rule is "A Trooper's Movement ends automatically whenever he enters Silhouette contact with an enemy, even if the specified movement route is cut short as a result." "Enemy" as a noun isn't defined in the rules. I'm inclined to think it means "enemy trooper," meaning touching the motorcycle token wouldn't stop movement. Whether you can walk over it: the General Movement Rules say "A Trooper can move through allied Models, Markers, and Tokens, whose Silhouette Template height is equal to or lower than the height of the Trooper’s Silhouette Template. The Trooper cannot end their movement within the allied Model, Marker, or Token." Token is on the list, so it would apply to motocycle tokens. The implication seems to be that you can't move over an allied motorcycle token if your silhouette height is lower than its height, and you can't move over an enemy motorcycle token.
You know the concept of house rule, right? I thought it was clear that it was one of them when I wrote «what we do is consider»; for future occasions I will make it clearer.
Outside of house rules, they are player owned pieces of equipment deployed on the table, much like mines or deployed FastPandas. Since it was deployed by one of the players, the other will consider it an enemy which means your movement stops when one of their troopers enter base contact with it for that player. https://infinitythewiki.com/Motorcycle When a Trooper on a Motorcycle declares any Skill with the Movement Label and announces he will Dismount, replace the mounted figure with a Motorcycle Token (MOTORCYCLE). Place the Trooper's Model in Silhouette contact with the Motorcycle Token, or measure his movement from the edge of the Token's base, as you prefer. A Motorcycle Token has the following Attributes: Name ARM BTS STR S Motorcycle 0 0 1 4 https://infinitythewiki.com/Terminology Token Game element that represents a piece of Deployable Equipment or a Deployable Weapon. https://infinitythewiki.com/Alignment Enemy Game elements that belong to the opposing player's Army List or to any of their teammates if the game is played in pairs or groups. QueensGambit provided the rules for navigating around or through them.
Remember that the motorcycle is ARM0 STR1, it's not particularly sturdy when not in use. If you were going to let someone use it for cover, you should adapt the mechanic from shooting into melee combats and have that shots that miss by 3 (the cover modifier) get resolved against the motorcycle. Edit: I apologize for going off topic. After I posted this, I remembered about the recently added proposed rules section, and that's where discussion of motorcycle house rules would be preferred.
As part of the house rule, the bike has no attributes, except the value of S (just to be consistent with the fact that it has a base). Accustomed to using all kinds of vehicles as scenery, to simplify things (at least for us) we consider that once the pilot is dismounted it is just another scenery element. And the truth is that it gives us good results and opens up interesting tactical options.
How does ignoring the fact that you can shoot and destroy the motorcycle (because it has stats) open up more interesting tactical options? "We're riding mobile pieces of cover" gives rise to "What you're hiding behind is easier to shoot than you are, and the enemy may have rocket launchers". Counter tactics make things more interesting tactically.
Who knows? What may be interesting to you may not be interesting to us, and what may be interesting to us may not be interesting to you.