The suffolk lawnmower is no more than a couple of loaded brake shoes really. If you examine the Honda clutch closely it has a series of kidney shaped pressings mounted on a ring that pivot trying to provide centripetal force and clamp the plates (this is what I changed through CNC etc). The really clever bit is how this action is overridden by the gear lever via a worm drive and thrust bearing--once the gear lever is released the clutch can then operate. The engine started with a rather light pushrod C50 I think, and then gravitated through to an OHC 50 and then an OHC 90 , with a long stroke 90 as an "economy" version--but please correct me if I'm wrong. The concept lives on through pit bikes, small scoots and that odd Honda 125 which is a bit between the little "monkeybikes" and a normal 125. My involvement was using this engine in the Shell eco marathon--I built a hybrid 58cc with the 90 economy bottom end and a 50 barrel and head (LONG STROKE). 14:1 compression ratio, reprofiled cams, twin plugs AND multi spark, and progressive lean burn--starts on a carb but in a period of about 10s a stepper motor controlled air bleed into the inlet tract eventually leaned the mixture right out until it stopped. (about 3 or 4 10s bursts to get around Silverstone club circuit at an average speed of 15 mph--my record was about 2200 mpg (many years ago), but the record now stands at well over 10,000 mpg--its a serious business!)Paul_C wrote:He covered the Centrifugal clutch when doing the lawnmower in series one.
ps hope this didn't put anyone to sleep before they got to the end!
