Elsie is the nick-name for the Yamaha two-stroke motorbikes that rocked the biking world in the 1980's. Unusually for the time, the engine was water-cooled, so Yamaha's name for the breed was LC, for Liquid Cooled. Say "LC" out loud and it sounds just like the girls name "Elsie". The name stuck.
So why all the fuss ? Well, when they where introduced, these tiny little 350cc bikes blew-off some of the current superbikes, ensuring that they became a legend overnight. They immediately dominated the production racing scene as no other bike ever had. More importantly, in the UK, a rider with no experience could legally ride the 250cc version. Even the government sat-up and noticed: New regulations were rushed in to slash the power allowed for learners. Today, you still find the most fervent Elsie fans in the UK.
Yamaha's fondness for contrived initials soon brought the YPVS evolution, or Yamaha Power Valve System. It is just a spool which lowers the exhaust port height at low revs, to make the power delivery more flexible. These later bikes are often called 'Valves', and some purists will say that they are not proper Elsies.
Other manufacturers have made better two-stroke bikes, and the superbikes soon improved enough to
comfortably outrun Elsie. So it is hard to say why, even today, no other motorbike has such a large and
enthusiastic following. It pulls in young riders as well as old, so it's not just the nostalgia.
Maybe looking at this web site will help you understand...