I got my engine back together with new tappets and one new pushrod.
For those who have forgotten the drama it all started with a tapping
noise at a rate about half the rpm, which was increasing in volume. I
found that the tip of one of the pushrods had separated, acting like
a metal golf tee riding free in the shaft of the rod, which was the
apparent source of the noise. I also found significant pitting and
wear in my tappets, especially those on the 1 and 4 cylinders, so I
replaced them all. In discussion with Darryl, the engine rebuilder
it looks like the tappets aren't rotating in their sockets so they
wear in one place. He attributes this to crank design and there
doesn't seem to be a remedy other than to change the tappets every
12,000 miles or so (mine had 18,000.)
Anyway, got it all back together and adjusted the valves to .0013
cold and it started right up. I wouldn't compare the sound to a BMW
motorcycle, but the tapping is gone. After warm up I reset them
to .0012.
Took a test drive . . . about 20 miles and it ran just fine, though
with a little gearbox noise under load, which in the past has meant
that the timing is a little retarded.
A few blocks from home it started hesitating and missing and we
limped home. I haven't had time to investigate, other than to check
that all the spark plug wires are in place. Next step, when I have
time, will be to recheck the valve clearances, set the timing and
check the carbs and ignition. I'll examine the spark plugs for
abnormal soot or whatever. There is a nagging fear of a burnt valve
or some major problem, but I guess I'll discover that as I go.
Any suggestions?
Andy Moyce
52 TD
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