Aftermarket products today make current bikes ultimately tunable. The Rollon eccentric cam throttle tube (price $ 50.00, grip not included) is just one of those products that can help fine-tune the feel and performance of your bike.The Rollon throttle tube has a cable-cam that varies the leverage your right wrist gets on the carburetor slide. In other words, the amount of twist it takes to affect power delivery of the engine changes through the twist of the throttle.The "YZF Slow" throttle tube changes the pull so that it takes more twist to open the carb slide in the lower RPMs. The leverage "catches up" at the end of the twist by ramping up faster at the end. The amount of twist to go from full-closed to full-throttle remains the same as stock. The benefit of Rollon's set up is theoretically more throttle control in the low RPMs a valuable tuning trick for technical riding or for a bike with a too-violent hit.On the WR 450F the throttle definitely felt slower all the way through the pull. The "ramp up" at the end did not feel any different from stock because usually when you open up to full throttle you just whack the thing open. The eccentric cam does not affect things much in those cases.The Rollon throttle tube definitely does what it was designed to do. On the WR, a bike so mellow and friendly, it made the power delivery too soft. In fact, it took away most of what little throttle response the big WR started with.This product works, it just needs the correct application. I intend to try it next on the YZF 450 to see if can mellow that beast. From my initial testing, I believe it will be a big benefit to that bike.The Rollon throttle tube does not make the throttle pull any harder or softer, but it should be noted that it will likely require a throttle cable adjustment once installed. It is made of plastic, which may not seem as appealing as aluminum, but consider that it never needs lubrication, and cutting it down to work with hand-guards is easy. It also comes with a free replacement guarantee if the tube breaks in a normal dirt related crash. The Rollon throttle tube is a quality product and a good idea that just needs the proper application.