Billy, honestly i don't know as i haven't been updated yet in regards to 2stroke scooter tuning in europe, they say the difference in hp between a 78cc & 86cc 2Fast pipe is 1 to 2hp at best but the torque output is more significant on the 86cc pipe for the 86cc setups.
my best bet would be to get a Roost pipe if you plan on running the 86cc kit & crank combo, for 70cc i still think the Yasuni C21 is still the best off the shelf pipe out there.
if i manage to get an 86cc 2Fast kit & crank i plan on using the 78cc 2Fast pipe first to see what we can coax out of the engine setup but for now it will be a distant reality as scooter racing here has slowed down to halt & we are much now into scooter circuit racing but more like a hobby than serious competition.
my best bet would be to get a Roost pipe if you plan on running the 86cc kit & crank combo, for 70cc i still think the Yasuni C21 is still the best off the shelf pipe out there.
if i manage to get an 86cc 2Fast kit & crank i plan on using the 78cc 2Fast pipe first to see what we can coax out of the engine setup but for now it will be a distant reality as scooter racing here has slowed down to halt & we are much now into scooter circuit racing but more like a hobby than serious competition.