I started a rebuild today for one of our members who have a nice, but high-mileage, 750K6. Here's the point to remember about this bike, before I get into more details: he flew to Michigan (or Minnesota, one of those States up there...) to buy it, then rode it back to home in California (3000 mile trip). On the way, he stopped by here (in Colorado) to talk about this rebuild, and he brought me the bike last week to start on it. He said the bike ran fine, but is fairly high mileage (I'll try to find out that number and post it later).
When I took off the top end of the engine today, I was surprised to find: the oil jets are missing!
The top end has recently had the cam bearings replaced, and the rocker shafts show signs of the high-mileage, so they were re-used despite the new castings being installed. The cam cover was glued down tightly (with copper-laced sealant of some kind) and every screw and nut Loctited but good. The #1 and #4 intake valve guides are quite worn, but no other unusual top-end wear was found - the cam looks to be very young, maybe 5k-10k miles, I'd estimate. Some of the Parkerizing is still evident!
So, as I go through the rest of this engine, I'm going to post the "wear numbers" here that I find. It will be interesting to see how the bottom end fared with NO OIL JETS at all in the top end!
Many years ago, a chopper rider I knew told me that some of his buddies were "making this oil mod" to their 750 top ends. I took it (and him) with a grain of salt, as he was a habitual prevaricator on many topics, but now, I wonder?