So, how screwed am I? - Exhaust cam

So I replaced the tach seal and o ring on my 79 KZ750 ( kzrider.com/forum/2-engine/601914-trick-...installing-tach-gear ) to fix a leak. Leak was fixed, but the tach wouldn't work after I replaced the seals. Engine started up but the tach wouldn't work. Now I see why.



I honestly don't know how I did this. Didn't feel like I was forcing anything, never heard a grinding noise, nothing.

So my question now is just how screwed am I here? I clearly need a new exhaust cam shaft. My concern is all the little metal bits that got torn off. I removed a number of them with a pick and a magnet, but I'm sure there's lots more in the oil.

Am I looking at a complete engine tear down and rebuilt because of this? Or will my filter have kept my engine reasonably safe?

Ouch :ohmy:
New Cam or electric tach.
Not really familiar with KZ twins , but I would pull pan and pull off pump and inspect pump internals. That should tell you somethings, then flush out all oil galleries with a lite solvent and air and collect what comes squirting out to have enough information to decide how far you need to go.
OR
Just tear the whole thing down to be safe and dont take any short cuts
Dave

You can try flushing the engine after dropping the sump cover. Not sure it's necessary. The oil filter will catch the bits as they are sucked up by the oil pump. You might want to pull the sump cover and clean that out when replacing the camshaft. No way i'd tear the engine apart just because of the damage shown.

I'd drop the pan and check for debris. Clear if found. Change oil and filter. Camshafts are pretty easy to change. I see "tear downs" on ebay sometimes where they sell every piece from an engine. You could get a canshaft and tach gear that way. Online dismantlers are the other option.

Yeah there are some cams in the 50-150 range. Sounds like the consensus is that i don't necessarily have to tear the engine down. That's a relief.

I wouldn't. The strainer will catch most of it. I would inspect the oil pump. It may be scored inside.
Steve

I've seen it before. Just change the cam, change oil and filter and you'll be good to go.

Any metal that gets past the screen goes through the oil pump before it gets to the oil filter. I would disassemble and clean it. The transmission shafts are pressure lubed and there lots of other passages that will need to be cleaned. You can also look into a motor swap, that may be a cheeper way to go.

I don't think so. :whistle:
Steve

swest wrote: I wouldn't. The strainer will catch most of it. I would inspect the oil pump. It may be scored inside.
Steve

At least drop the pan and clean it out..... betting the pump strainer has metal stuck in it..... I replaced mine (strainer)...... removing 38 years of sludge stuck the bottom of the pan will do the motor and oil changes good anyway.

That's a given. The pan has to come off to get to the pump. It may have scratches in it. They can be taken out with #600 paper.
Steve

Yep, I'll be sure to remove the oil pan an inspect the pump too!