Godfrey DiGiorgi wrote: > On Sep 19, 2008, at 12:49 PM, Maxime Thériault wrote: > >> http://www.robertstech.com/temp/piston.jpg > >> What's the story behind this? Do you know? It seems almost >> impossible that a gas explosion would do this. > > That's usually what happens when a valve breaks and falls into the > combustion chamber, although detonation can cause a piston to melt and > look similar.
The story: In 1993 I put together a team to ride the last motorcycle 24-hour endurance race to be held at the (in)famous Nelson Ledges road course (http://www.superbikeplanet.com/2004/jul/onthisweek10.htm). We rode my Yamaha FZR400 and did very well under brutally hot conditions, taking 3rd place in the 600cc class (because they'd eliminated the lightweight class). The following spring I rebuilt the engine (running at/near redline for the best part of 24 hours is pretty taxing on both man and machine!) but, because I was coming off a long bout of unemployment, I was almost broke. I did all the work myself, putting in pistons, rings, main and rod bearings. I just didn't have enough money to put in new valve springs. I thought I could put it off for a race or two. The photo shows how wrong I was! -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
