I thought you guys might get a kick out of these photos. I was recently presented with the "opportunity" to dig back into my '76 "Ironhead" Sportster that I rebuilt a couple of years ago. The darn thing broke the exhaust valve spring on the front cylinder, the valve hit the piston, and the head of the valve broke off. Made a bit of a mess...
I wound up having to replace the cylinder, piston, both valves, both springs, and the guides on the front cylinder. The head and rocker box, miraculously, survived. An inspection of the rear cylinder and head revealed a broken exhaust spring there as well, so all springs have now been replaced. With a different brand, by the way.
So here is what a real old school, 1950's era technology "hemi" head looks like. It's hard to capture in a photo just how deep the dome really is in these things. That massive dome on the piston only brings compression up to 10:1. Talk about dated technology... the valves and ports are massive on this thing, considering its small displacement and relatively low rev limit. My, how times have changed.
Oh, and check this out. Dan Baisley's own, in-house roller tipped rocker arms. These extend valve guide life tremendously in the old Harleys by eliminating any side loads between the valve stem and guide:
I should have this all buttoned back up tomorrow. Nice little rainy Saturday project.