I've wondered if these would work, they are used in our bikes to retain the relays rack in the battery box. They are also used on cars to retain bumpers and trim panels. Seems like you just need to know the hole size, but I don't have that chin cowl. As you know, you just push the pin further down into the housing to release the fastener. Then you would (for example) lay the cowl down, insert the housing thru the cowling mount hole and into the hole on the bike, then insert the pin (pic) to lock it. They handle lots of abuse.
Again, I don't know if these work in threaded holes, or only in thinwall holes like a hole in a plastic widget.
http://shop.northlandfasteners.com/N19231-Push-Type-Retainer-N19231.htm
wildbike:
Thanks. I'll just go with the zip-ties to hold the lower cowl on, and make it easier to access the current oil filter.