bazzee said:
Hi Piet,
what was the nature of the failure? Fatigue of some sort?
Do you have an 'after' shot that you would care to share with us? It is fascinating to get a glimpse into a works motor.
Cheers,
bazzee
Very probably "fatigue of some sort"!
I was warned about keeping them in the motor, but I figured if Virginio, Marco et al could ride 12/10ths with those things and they lasted (this long), they'd hold up quite OK if I tootled around various tracks at 80% max. Couldn't have been more mistaken, unfortunately.
I was very reluctant to pull the crank apart because it ran just about perfect, these are a true bugger to disassemble and get straight and true afterwards. The bike is still as it was after the SRC event at Paul Ricard, I'm hoping to find some time to remove and disassemble the engine after Chrissie. Pics will follow. Thankfully, a pair of Elettronica pistons and Carillo rods are in stock, just need to find a liner and stuff some rags in the gaping crankcase holes...
As Paul stated, the motor should carry a very special head, with short rockers and shallower valve angle. Instead, an early Elettronica head is fitted, together with very strange pistons. These were probably the cause of the bike being retired long ago, as all valves were bent due to contact with the pistons. The valve cutouts had been machined incorrectly, suggesting these may have been manually machined prototypes for evaluating the new at the time head. I re-worked the cutouts and fitted stock SFC valves and away we went!
For Robs benefit, I've attached a pic of the special timing chain damper wheel. (Note the dates on the photos, shipping to Eastern Creek only days away!)
I reckon the race track was used mainly for evaluation of parts and new ideas, long and tedious road tests rarely show up shortcomings that become glaringly obvious after only a few track laps/hours. No computer simulations back then.
piet
