lock it up

After changing the front end on my 86 FXR from a 35 mm to a 39 I have no fork lock on my tripple tree (dam those new and improved bikes) and need a way to lock my bike while I'm out and about.. I don't like the disk lock because I will forget about it. Got any ideas?

You could use a chain like the Kryptonite style or the big lock that goes through the wheel and keep it in your saddlebags. Or, you could use a disc lock with an alarm. Position the lock so you cannot move far either way i.e if you have to push forward to leave, place the lock as close to the caliper from the rear so you cannot go to far forward without it hitting the caliper.

I have seen quite a few "remove before flight" flags hung from wheels to help remind the rider.

BTW, it only takes one time to permanently be able to remember it is there.