Joe,
no, it's almost a partial seizure, since an engine which has suffered that doesn't usually recover afterwards.
Instead, the damage to the piston(s) and barrel(s) means that there's a loss of compression on one or both pots and generally very poor performance...
I'd be listening for high speed detonation, also checking the total amount of ignition advance, spark plug heat range as well as the condition of the oil cooler.
However, is there any chance that it's fuel starvation, which would result in poor running under full load and/or speed, but would improve very quickly once the throttle was backed off?
Of course, the problem would happen again once fuel demand increased beyond what the pump was able to deliver to the carb.
Keeping the pedal down even when the engine's protesting means that it's being forced to run on a weak mixture, which will burn slower and soon cause overheating.
Paul,
if it was a worn out clutch, wouldn't that be much more evident when accelerating through the gears and be most noticable around 3,750 rpm, when the clutch is required to transmit peak torque?
It didn't take my daughter too long to give me a call when the clutch on the 2 pot Visa wore out, since the lack of go in relation to throttle position hindered progress dramatically (even in the flatlands around York where we live).
ken.
Gay_Joe wrote:
so when they get all hot and spluttery and start kangarooing... thats a partial seizure?...
) 
