Topic: The mystery goes on

[Steveola]

I posted a while back that my upper end had stopped oiling and I had scored the camshaft and journals. Well I've got the engine out and have the upper end off. I still hadn't found anything that would tell me what happened. I've got the engine in a stand and when I flipped it over to pull the oil pan I found a $hit load of shaving and what looked like fuzz in the oil pump screen. I have NO idea where the heck THAT came from. I thoroughly disassembled and cleaned the engine. I haven't split the cases yet, which I will do tonight after work, but so far I haven't found any crap in the engine just looking in where I can see. I'm thinking the oil pump screen got plugged and my oil pressure went down. I plan on completely disassembling the engine just to make double sure all is well. The first thing that came to mind is that I purchased an oil tank off eBay and I may not have got it good and clean. It may have had some crap stuck to the bottom and when the hot oil started moving through it it started to break up. This bike is a "mostly a 1976 CB750 K. It started out with just an engine and I sourced the rest from various places. The bike has only 52 miles on it since I put it together. This is my first CB750. It's been an um..education. From now on I plan on sending oil tanks to a radiator shop to be cleaned. Does anybody have any advice as to what to look for? Thanks. You guys have been great with all the help in the past. I would have been soooooo lost without it.

[lucky]

That fuzz could have been a rag ?
You are smart to take the engine apart.
It is common that someone will stuff a rag in a hole then later forget they put it in the hole. Cotton rags or fibers around engines are engine killers.

[Sniper X]

Whilst I was but a wee lad of about 16, my first car was a 1969 Chevelle SS with a 427 swapped in. Every once in a while, I would notice the oil pressure going to ZERO and would shut it down. After a second or three of being shut down I would fire it back up and it was back up to 80psi or so......Did this for about a year, then when I took it apart for a new oil pan, HV HP oil pump, and such, there was a 1/2in box open wrench AND a red shop rag in the oil pan! The rag would get sucked into the oil pick up screen and shut my pressure to zero and once I shut it down, it would fall away and not get sucked up again till a week or month later. I drove this care for like year with it doinjg that till I figured it out!~ Luckily never blew it up.

[Brantley]

Did you pull the oil jets in the head (beneath the rocker towers) yet?

[Steveola]

I didn't realize they came out. How would you get them out without damaging them?

[Brantley]

After you dig out the o-rings they should pull out pretty easily, or even fall out when you flip the head. If not, look thru the adjacent cylinder stud holes and you'll see the feed passages about an inch from the top. Coax something like a WD40 straw in there from the bottom and push it out. I would probably shoot some carb or brake cleaner and compressed air down thru the jet first to loosen any schmutz that might be the cause of blockage. Definitely do that to the rocker towers' oil passages, too. Possible TMI: This is assuming that your head hasn't been swapped somewhere along the way with a K0 or K1. Those had different "oil control orifaces" that are a real big pain to get out without mangling.