Thanks, Shiloh0. It is my quickest bike.
bigalan, with 25:1 oil/fuel ratio, this sucker spits out a lot of oil. I might have mispoken; ya need to wipe the oil mess after every run. Then again, my Tanaka has 50:1 f/o ratio and still spits quite a bit of oil too.
Be sure the engine is well-insulated, or your hands might get numb. I insulate my engine drive system with swatches of bicycle tire, not bicycle tube. They work well.
The clutch spring broke recently and the 5:1 tranny needed relubing. After filling the tranny with grease, the 460 was replaced with a 2.8hp Tanaka 47R engine. I mounted the Tanaka upside-down too, so that I was able to re-use the Happy Time expansion pipe and HT 4-liter fuel tank. Engine size is similar, although the 460's exhaust tube hugs the bike frame tighter.
The 460 with SBP expansion pipe is MUCH quieter than a Tanaka 47R with the same pipe. With the Tanaka being so loud and all, it's hard to wind it up to its max. It's no slouch, though.
For the price, ya just can't beat the GP460 engine. It's the most powerful engine that will bolt onto available engine drives. The shift kit and the NuVinci hub work extremely well with the 460. Single-speed systems won't work well with hills.
For the amount of power it produces, the 460 has excellent gas mileage, much better than the Tanaka.