Overall I'm quite happy with the Booster motor. It's probably done about 35 hours now. I have a few niggles with it, and to be honest, the factory haven't been very responsive, although I haven't pushed them too far. The main issues are:
1. Fuel consumption - I was expecting as good as my top 80 but I'm getting about 4 l/hour on a Nucleon 27 with AUW 105kg, mixed trim settings.
2. Spooge - It oozes graphite-like spooge from the seams in the carbon silencer. This goes all over the prop. My mates doesn't do this and it could be linked to rich running and the high consumption. The only response I got from the factory was "turn the low end mixture screw in 1/4 turn". I know the WG-8 carbs inside out and that isn't going to make any difference. I wanted to check pop off pressures, lever height, spring, etc, but the factory won't give me any settings. Not like my top 80, where there is an abundance of information.
3. Belt slipping - The belt needs to be really tight to prevent slipping at high rpm. Factory response is that it isn't a problem!
4. RPM - If you use the 130cm prop then you won't get the max published rpm, it will be a few hundred less. I tried both props and only got peak rpm on the 125. I think that the only difference between the two eprops is the length. They haven't put a finer pitch on the longer prop to bring the rpm to spec. This isn't a huge issue for me but it's good to know in case you think your motor is down on power.
On the plus side, it is light, relatively easy to start if you get the priming spot on, and has a little more poke than the top 80. Throttle response is great and it makes a lovely 2 stroke crackle noise like my old KTM!
Steve