So.... I BLEW up my motor.... literally...

So it NEVER ends... Took the bike out for a little ride today. I was running great... I figured out my petcock problem... the idle had gotten better...
Then all hell broke loose.
I opened her up for a second... not red lined or anything, but really gave her some throttle and BANG... I felt something hit my leg and the motor got really loud all of a sudden... it still ran, not well, but it ran... I noticed a bunch of oil spraying out onto my exhaust and headed home.
When I got off I saw what had happened... there was a golf ball sized hole punched out of the valve cover on the intake side. A HOLE. A BIG F&^%ING HOLE
Now, my question is... what would cause THAT huge of an impact but not totally seize up the motor? I retrieved one chunk of the valve cover and it appeared to have an impact mark on the inside... but what could it be? The cam cap coming loose? I haven't taken the cover off to inspect anything yet, but I'm just trying to troubleshoot in my head right now.
So this is it for me... it's been fun learning about these bikes and rebuilding this one, but I can't take the heartache anymore... I'll be selling it as a project if anyone is interested... new paint, powder coated frame, new wiring, etc...
Thanks to everyone who has helped me along the way.
I'll post pics of the carnage later.

Cool! Maybe a shim worked it's way out...What lift cam are you running? Please post some pics when you have a chance.

Don't get too discouraged. It's all in good fun as long as no one gets hurt.

What modifications have been made to the bike?

With no pictures, my guess is it threw a shim.

Better than my experience. My engine seized up at regular cruising speed. Turns out something in the cam train came lose, wrapped around the cam chain, then proceeded to generally tear some shit up before seizing up. Happened in about .5 of a second and it was fun holding the clutch lever in while i pushed it home.

I bet its not hassle if it was still running and something has just flown from the cam cover. If you were selling it, it would be a pretty good project for someone.

I had new valves and some light port polsihing done by Larry Cavanaugh. He also sold me a set of Andrews cams, but he said that I didn't need any other upgrades to run them... and I trust him.
Other than that the bike is basically stock, except for I'm running BS34's on it....
It has new rings, new top end gaskets...

Sorry, dude. That is terrible bad luck or maybe the Devil just had nothing better to do.....

could a shim REALLY do that much damage? I'm serious... a golf ball sized hole in my valve cover... maybe I'm just crazy, but one of those little shims doesn't seem like it could have done that. If so, do you think it would be fine to replace the shim and valve cover?

Well, i would take the valve cover off, you'll see if its a shim in one second.

But ya, i bet it could do that. The thing about aluminum is that it will crack away instead of bending. If you threw something out of your oil pan on an engine, the hole will be more or less shaped like the thing that went thru it, cause the steel will give way.

Aluminum will just shatter (most of the time). Those cams might have a bit too much pitch and maybe it was wearing away at the bucket and it just gave way when you gassed it.

Take the valve cover off and find out. If there is any damage to the bucket, better replace it too. Might want to fool proof it and get those buckets where the shim is actually UNDER the bucket instead of on top.

Post again when you get that cover off, i'm curious myself.

alright... will do... I guess it goes to show how strong these motors are... the damn thing made it all the way home... god I hope I didn't do more damage getting it home.... haha I just put new damn rings on it.

Sounds like a shim to me. You might have gotten lucky and will probably need to replace the cam, bucket and shim. The damage to the cam would be from riding it home and the lobe slapping on the bucket.

Bicycle Lee wrote:

I had new valves and some light port polsihing done by Larry Cavanaugh. He also sold me a set of Andrews cams, but he said that I didn't need any other upgrades to run them... and I trust him.
Other than that the bike is basically stock, except for I'm running BS34's on it....
It has new rings, new top end gaskets...

thinking i would ask for my money back if it's a missing shim.

Bicycle Lee wrote:

could a shim REALLY do that much damage? I'm serious... a golf ball sized hole in my valve cover... maybe I'm just crazy, but one of those little shims doesn't seem like it could have done that. If so, do you think it would be fine to replace the shim and valve cover?

Yes, definitely a shim can spit out and take a chunk of head or valve cover with it. Those cams shouldn't spit shims though.

Those are Andrews drop in cams. They do not require shim on bottom. They're only .340" lift. It's the early version of their 2X that was later called the 1X when they increased lift to .365" lift. It's a very mild cam.

The only Shim On Top setup I've ever seen spit a shim is the Andrews 3X cams would on occasion [not always] spit a shim.

Never, ever, saw that happen with a any other drop in cam. Pull you valve cover and see what it looks like.

You've had that head back since way back in late spring, early summer and all of a sudden it spits a shim with mild cams......hmmmmmmm. Yank the valve cover and let's see what's going on. Call me when you get it off.

Walter - you should stay out of things you know nothing about. Next time you need a free alternator rotor, call somebody else or cough up the $600 that Kawasaki wanted for one.