Early 650 motors used many parts manufactured during the final days of the Zanini incarnation of Laverda. The castings used for the head and barrels are reputed to be of very high quality and I have not, as yet anyway, heard of any problems with these cylinder heads. As supplies of these early parts ran out, a different foundry was commissioned to produce additional quantities of both heads and barrels.
Apparently, there was a mistake made in the selection of the alloy for the head castings, leading to a problem where at high engine temperatures the valve seats can move in the head, with subsequent valve damage. This, coupled with attempts to reduce other heat induced failures, led to a redesign of the cylinder heads and a new batch of heads was manufactured by SCF of Reggio Emilia. The changes were incorporated progressively into the later 668 engines as they were manufactured, perhaps not all at the same time. I do not know at which point each of the changes was made, but it was certainly the case that this process was not complete until after the manufacture of my 668, engine number 2072, some time in 1996.
It has been suggested by Mick Walker in his Laverda Twins and Triples book that the changes were introduced during 1996, part way through the 668 model run.
The factory upgrade kits come complete with valves, springs, shims and buckets, but minus the cams. The original cams are therefore taken from the old head and fitted to the new head. If the kit is supplied under warranty then the old head will need to be returned to the factory.
© Steve Carr, 2001-2007
Site created February, 2000. Last modified Friday, May 15, 2009
30 May 2005