Always on the lookout for cheap and easy, I found some grip heaters on Ebay from: http://www.nativearrowracing
. I think they are made for snowmobiles. These were only $26.00 w/ shipping and let you re use your own grips. They are a heating grid that go under your original grips. They have 2 temp settings, the high was very warm and good for startup, but then the lower setting is just right from then on.
Removal of the grips is easier than you might think, if you are willing to cut them a little. I scribed a circular cut about 1/2 inch from the ends, about 3/4 of the way around. This still leaves them in one piece. The idea is to get a long skinny screwdriver, filed down for smoothness, under the grips, to break the factory glue seal. Once you peel back the cut end you can work the screwdriver in and around the grip, and shoot some WD-40 in there if necessary. They came right off! Install the grip heaters, and with a very small dab of oil on the end, slide the grips back on. I mounted the switch on the right side plastic piece ahead of the fuel tank. I hid the wires inside small black tubing, same size as the brake cables, and used the auxiliary power plug inside the headlight housing. I have not checked the current draw but as it is my only accessory, it should be ok.
Two issues: One is the right side does get hotter more than the left, I figure because it only has to heat the plastic throttle sleeve, and not the cold bare metal end found on the left side. Not as noticeable on the lower heat setting. Also, the wires on the right side do move as the throttle is twisted, not the ideal situation, but will probably never fatigue to the point of failure.
Didn't take time to take photos as it is near freezing in the garage and once I got on a roll....... Hope my written directions make sense!
Live Long and Prosper,