When Cruise-Mate owner/inventor Tom Lane started riding Harleys, he had the same problem most people face while riding a motorcycle—holding the throttle open for extended periods of time without hand discomfort. He wanted an improvement on the Motor Company’s offering of the thumbscrew throttle lock.
In 1974, Harley began adding a thumbscrew on the bottom side of the throttle grip that allowed you to advance the screw with your thumb until it put pressure on the grip. The pressure, when tight enough, would keep the throttle open while you stretched your hand. The problems with the design were twofold; it was too small and it took too many turns to engage/disengage. Great idea, but it needed to be redesigned.
Tom wanted something he could push on and off, much like a turn signal, without taking too much time. The time issue was most important when you needed to disengage it. He set out working with the original thumbscrew’s threaded hole, but soon realized the thread pitch was too fine. For quick advances, he knew he would have to alter the housing. He learned from trial and error and created a product that works like a charm.
When I received the product, with it were the necessary pieces to assemble the device and also the step-by-step instruction sheets. I noted that the parts were well machined and looked simple to install. They were made from 303 stainless steel, so they will not corrode or rust. Looking over the instructions, my impressions were confirmed. With the detailed directions and several pictures to identify the process, this would install in no time.
Start the disassembly by taking apart the housing and detaching the throttle cables from the grip and the housing. Next up, you need to enlarge the existing threaded hole after you remove the original thumbscrew. A drill jig installs on the housing, ensuring positive alignment and straight drilling. Once tightened down, you proceed to drill the aluminum housing with a 21/64 drill bit. After drilling, you remove the drill bushing from the jig and thread a 3/8-24 tap through the housing. It’s that simple. Care must be taken to clean out the aluminum shavings from the housing before you begin the assembly. Screw the base of the Cruise-Mate cartridge into the hole with a drop of LocTite until fully seated. Re-assemble the housing including the cables to the original position and install the handle, spring and bolt on the Cruise-Mate. You are now ready to adjust it.
Adjustments are simple and quick. The handle is spring loaded, allowing you to pull down and advance it till you have the throttle locked in the open position and the handle toward the front of the bike. Rotate the handle toward the back of the bike and the throttle should spring closed. This adjusting feature allows for wear in the product, as you can re-adjust it one tooth at a time. The wear surface is made from Nylon 6/6, a very durable plastic. The instructions cover adjustments and it is listed as infinitely adjustable.
I installed the set-up on my wife Kim’s ’03 Electra Glide and after a suitable amount of begging, she let me take it out for a test ride. Operation is easy. With your thumb, you push the handle on and flip it back for off. While riding along, you can easily increase or decrease your speed by twisting the throttle either way. You don’t have to flip the handle off. I liked it so much I got one for my ’81 Shovelhead, where it works just as well.
The product is an excellent upgrade to an existing Harley, and Big Dog Motorcycles now offers it as an option on their bikes. The product is also available for metric bikes. The Cruise-Mate website offers fitment information, installation pictures, instructions, customer feedback and a list of places you can get one installed. The kit doesn’t include the drill bit or tap, but any good hardware store will have them. The instructions state the product is intended for motorcycle warm-up and service only, but Tom tells me he invented it to replace the existing thumbscrew and relieve the numbness in his hand when he rides. Necessity is the mother of invention—use it however you see fit. You won’t be disappointed!