I really recommend splitting the case and a good flushing! I had the same exact thing happen, and my inexperience cost me a set of flywheels & $, and lots of downtime.

An out of round lifter roller jumping off the cam lobes will cause tappet block to crack, because the lifter will have side to side movement with every up and down. The metal debris from the lifter is the engine killer. Your oil filter will not catch it all. Here's what I replaced when this happened, BUT I didn't flush out the bottom end: tappet block, lifters, oil pump, new oil lines, flushed oil tank, etc... All this, and the debris hiding inside the crank still took out the engine 1000 miles later.

Learn from my mistake, and save $$ and headache by doing it right. Good luck.

 

Aloha,
am I right to see some black spots in the housing from a broken breather valve gear?

 

The black spots were actually grey when I touched it....assuming it was tiny metal ground up shavings. Not the best lighting for pictures.

I don’t understand how the plastic breather gear didn’t get destroyed in the process.

And for splitting cases.....we’re 50/50 on doing that. He’s saying he’ll just changed oil/filter much more frequently and hope for the best. The bike wasn’t having any oil pressure issues.

 

Did you pull the breather gear out of the bore? I have seen pieces go through and screw up the bore...

 

Those pieces never made it past the lifters or pushrod covers, they blew outward.

 

Definitely need to pop the oil pump cover and breather gear for a looksie.... There is metal throughout the motor from the lifter and possibly the cam... Right now that metal is like emery cloth....

 

I kind of agree with Dan, wouldn’t you see damage in the cam chest or at least the plastic breather. I would expect to see some remnants at the bottom.

 

Removed the breather gear and the bore looks great. No damage whatsoever in what I’m seeing.

 

They make/sell an inline prefilter or screen that is 40 micron, and has a magnet (I know lifter block is aluminum but the lifter roller is not).

JP sells them, and there are other brands and price points. Sorry can't post a link on work computer. I say put it in the line between tank that feeds pump. Just a thought if you decide not to crack it open. I agree to check out the pump, but cheap insurance and something you can monitor.

 

I would not put anything that can restrict oil flow in the gravity oil feed line to the tank.

I would split the cases, that engine should have a complete overhaul.