I did a bit of digging for the California "locked, trunked transport only" rules (except bikes don't have trunks).
One basic seems to be, so long as you can't get to it while rolling, that's a good start. Many sportbikes have small storage areas under the (lockable) seat, so as one example, put it unloaded into a lockable softpack and then lock it under the seat, you're in good shape. There seems to be different opinions on whether or not there can be ammo separate from the gun inside the "inner locked case" - some say it's legal, some cops swear it isn't. I have no clue. But, it seems to me if you're going to try and obey the law, you won't be able to get to it in "high speed mode" anyways so you might as well put the ammo someplace totally separate and make the cops happy. Where easily practical I disassamble the pieces too, as in "pull the cylinders on SA revolvers".
I guess what I'm saying is, if you're pulled over and for some reason the cop is asking about guns, if it's clear they're locked, unloaded, unaccessable AND disassembled, the cop is gonna realize you're trying to be cool and you're more likely to escape a ticket
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Given the image some cops have of "bikers", going that extra distance seems prudent
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If you are passing through a shall-issue state and you have a permit elsewhere, definately check the reciprocity tables at:
http://www.packing.org
Jim