5 dollar suit case lock from Wal-Mart around the d-rings and mirror stem.

 

I use one of these either on the bars or down near the shifter through the frame.

 

Mine came with the HD one attached to the handlebars.

 

I use a regular bicycle cable lock and slide the cable through the D-ring or strap in the helmet; depending on helmet. The nice part about this is I can also secure a jacket (run cable through sleeve) if I wanted to along with many other goodies.

 

This is similar to what I use above except mine is combination lock.

 

+2 on the cable style gun locks. Very inexpensive and will adapt to almost any bike. Have been using them for years on multiple bikes. Lock to mirrors, crash bars, bags, frame, floorboards, tour pack racks, etc.

 

I use a bicycle cable lock also. My seat has the hole where the backrest goes so i ran the cable through a bracket under the seat and out through the hole in the seat. When you aren't using it just push it into the hole.

 

I use this Kryptonite cable lock on the rare occasions when I feel the need to lock up the helmet.. I got it for about $20 at Motorcycle Superstore (http://www.motorcycle-superstore.com...FcldTAod0hUARA) It has the advantage of a 3' long retractable cable. You can run it down the sleeve of your leather jacket (which is far more likely to be stolen than a helmet) if you don't feel like carrying the jacket along.

 

Pair of handcuffs works.

 

I use a Master cable gun lock. I set my wife's and mine's helmets on the rear seat and luggage rack then run the cable through the helmet strap webbing and luggage rack.

http://www.ebay.com/itm/Master-Gun-C...item2a2288fc60

Mal