The Motenergy ME0913 in the Zero S claims 30 kW. Zero's liveforphysics says that's rather optimistic, but they've heavily modified the motor and it puts about 30 hp down at the rear wheel. So let's back up and say the motor is putting down about 35 hp, or around 27 kW peak. ME0913 weighs 35 lbs.
AC-20 is 50 hp peak, weighs 53 lbs.http://www.thunderstruck-ev.com/ac-20.html
Perm 156W used in the Empulse concept weighs 31 kg (68 lbs), claims 30 kW continuous if I read their spec sheets right. Should easily do 40 kW (53 hp) peak.
Conventional motors at 150 hp would be far too large. Chip Yates didn't exactly have a 450 lb bike, nor a 20 kwh pack.
Yasa has a motor under testing which claims 165 kW (215 hp) peak, >85 kW (>110 hp) continuous. They claim a motor weight of < 20 kg (< 44 lb).http://www.yasamotors.com/technology/products/yasa-400
They have a motor more focused on torque than power which is available now.. I wonder why we haven't seen any race bikes using that motor. Although, gosh, those motors sure look like they'd fit nicely on the Mugen bike... ; )
CHAdeMO should be doable with a 20 kWh pack designed for high charge rates.
Even if the YASA motor or a similar motor is possible for production, a heavier-duty radiator, much more powerful motor controller, much heavier-duty transmission will all add weight. Brammo's batteries are already quite dense, at around 190-200 Wh/kg (as far as we can tell). Envia claims 400 Wh/kg, but they're really more like 310 Wh/kg and won't be available for a few years. To fit a 450 lb budget, we'd probably need batteries 3x as dense.
I'd love to see it happen though.
Edit: here's what Asphalt & Rubber
says about the Mugen Shinden:
Curb weight: 260 kg / 573 lbs
Motor Type: Three Phase Brushless DC motors
Horsepower: 90kW / 120hp
Torque: 220Nm / 162 lbs•ft
Battery: Lithium-ion Battery
Battery output: 370V or more
Here's the YASA-400
Motor Name YASA-400
Peak torque @ 400A 400Nm
Continuous torque 220Nm
Peak power @ 650V 165kW
Continuous power >85kW
Peak efficiency >95%
Dimensions 280mm x 75mm
Total weight <20kg
Maximum speed 7500rpm
At 370V, the motor won't peak anywhere near 165 kW. I think the YASA has to be it though - the casing is the right shape and size, the torque lines up exactly, the continuous
power lines up (generally people quote a peak power, Mugen is sandbagging!), the YASA is a three-phase brushless DC motor..
Probably the Mugen has 16+ kWh of battery onboard, at let's say 160 Wh/kg with packaging that's 100 kg or 220 lbs. At 573 lbs in a RACE bike, a next-gen Empulse would need to drop 120 lbs while adding lights, a gearbox (?), etc.. without being made of carbon fiber or unobtanium.