This SMT came to us all the way from Dorset with a Motohooligan airbox which the customer had fitted himself. He’d added a K&N filter to the engine breather pipe (which is ok) but the important thing to do is keep the length in the pipe. These engines don’t ‘breathe’ too heavily but even so we’d tend to route it back into the airbox, just to deal with the slight oil mist that may be generated. Venting to atmosphere could be an issue if anything goes wrong…

After the ECU remap power was respectable, 117bhp, but not the best we’ve seen. We did one with a DNA airbox, which is slightly more restrictive than the Motohooligan the same week and that made 120bhp. An airbox acts like a lung, and each engine requires a certain volume shaped to create the correct airflow.

All the way from Dorset for its ECU remap...

All the way from Dorset for its ECU remap…