The GEBE system is pretty good - the only thing that I have found is that with the trim panel mounted on the mount there are some amounts of vibration and noise.
As far as power is concerned its fine - and its getting faster although there is some pinging from the outside side of the engine occasionally (away from the fan, excess heat?). The top speed now is enough to keep up with traffic in 30mph limits and given the van drivers round here I am at least looking at 25-30 mph cruise and maybe a little more flat out. A four mile trip round and back to town with me riding in town (about 1/3 the total journey) gives me an average of 20 or so miles an hour (in rush hour)
The muffler seems to do its job and does serve to lower the note of the engine and it also makes it quieter.
The machine has to be pedaled to move away - as doing otherwise would most likely fry the clutch in short order and is unlikely to work anyways as the engine doesnt have the torque to do that. I usually ride up to a reasonable speed (ie to a stage where I would be at a stable pedalling cadence) and then run the engine up..
incidentally - as the clutch is a friction type that connects at 2000rpm would it be possible to fit some sort of motor to the rear wheel as an electric starter (ie starting from cold on a stand..). I just dont know if spinning the wheel side would engage the clutch to the engine side and spin it up...
Jemma xx