What part of the shaft broke?
You can fix it if the steel pin that is 90* to the camshaft and driven by the 2 allen heads that hold the air pump pulley onto the end of the camshaft wore out and broke.
That steel pin runs dry where it is driven by the top of the allen head bolts and eventually wears through and breaks. The tops of the allen heads get worn down too and a little 60% moly paste or molybdenum grease would help there.
When I replaced my cams, rocker arms and shafts a few years ago I noticed mine is worn almost halfway through after 125,000 miles.
I'll have to address that soon before it wears out and breaks off.
Cole recently noticed his is worn too and I think he posted a way or suggestion to replace that pin.
Moly paste is a good lubricant for something like this since it is 60% molybdenum disufide which adheres to ferrous metale like steel and iron and won't fling off.
Moly grease only has around 5-7% molybdenum disulfide in it.
