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

What a bummer. Funny thing about machines though.......they often and always give out. The more you hotrod the more you stand the chance of failure. You should be able to rebuild it easy though. I would go back stock and enjoy the bike.

hoghaterkaw wrote:

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.

larry didnt install the head,just did valve job how the hell do you think hes responsible for that?valve clearances need to be checked after head is torqued down on to motor and at regular intervals till things are broke in

Did you put all "new parts" in ?

I've been hearing horror stories about how the tops of high lift cams are being sheared off after engine rebuilds unless the oil has the zinc additives (which are no longer available in most oils) added in. Don't know if it applies, you probably used the right break in lube.

Two things.

1)I wouldn't even THINK of fixing that engine without a complete teardown and thorough cleaning of every part in it. Since you rode it for a considerable amount of time after the failure, there is undoubtedly metal filings throughout the engine.

2) I wouldn't put it back together without replacing the shims and buckets with KZ650 shims/buckets. Cheap insurance.

larrycavan wrote:

I'm wondering what was rubbing on the spots pointed to by the yellow arrows in this photo.

Larry hit the nail on the head, with the yellow arrows. Eighter rubbing or oil pressure? It takes alot to score the cams like that. Steel against alum., most of the time, steel wins. In this case, there was no winners.

That wear on the cam jurnal area, can only be from three things. Clearance, lack of oil or dirt.

Did you blow all the oil out of it, on the way home? Got any oil left in the pan?

I still think the shim went frist, then lack of oil killed the rest of it. I agree! Now your in for a complete rebuid. It is better to be safe, don't spin your own wheels.

I would be interested to know if that bucket, will even come out of the head now? I bet it's hammered in there, pretty good.

Don't give up yet, were hot on the trail.

Keep the pics coming!

I forgot to ask a basic question. Did you use new shims, with the new cams?

If it was used shims, I'll change my guess. I am hoping guess are free?

The used shim with a wear pattern, flattened the lobe on the cam, the cam then spit the shim, lack of oil roasted the cam bearing and who knows, what else.

Maybe I missed this but what condition were/are the CAM cap bearings?

Again, something to think about, no need to reply...

Considering that camshafts are hardened steel, I would think for that wear to be accomplished it would have been making one hell of a noise (grind/squeal) pre explosion...

Well unfortunate as it is, you have some work ahead of you and it can be done... Most of us have been there with the "WTF, Oh NO you didn't"...

Mine was blowing a hole in my cases, not paying close enough attention. The worst case was having to announce it for I now need new engine cases which as are a matched set... This crowd can be ruthless... :laugh:

But it didn't stop me, sure threw a wrench into the works for ~ 4 months (long story with seller) but I patiently waited it out, dealt with it and now am riding her... So can you...

OMR

A couple of thoughts,
1 if for some reason the bucket and shim were not rotating, that could cause excessive wear on the shim and cause a failure

2 a small fracture in the shim itself prior to failure

3 looking at the marks on the cam pointed out by larry, those could be from debris from either parts of the shim or valve cover, but a complete investigation will be needed.

4 possible bad lobe on the cam to start with, I dont really think that was the cause, but its a possibility.

5 last but not least, just plain ole, poop happens.

I would still pull the head and pan, get the head rechecked. all the valves and guides, and clean all the metal out of the bottom end, If it were mine I would pull the engine down and make sure all the oil passages are clean, and there has not been any other damage due to metal fines traveling thru the oil system

I am not a mechanic. I'm a guy who really wants to ride a motorcycle, not work on one endlessly. I've learned a lot and I value that, but at the end of the day I didn't buy this bike because I wanted to rebuild it time and again.

With as much money as I've thrown into this thing I could be riding a new motorcycle.

I can see replacing the valve cover, shims, cams and gasket, but beyond that I don't know if I'm up for a total teardown again, which is basically what I'm hearing I need to do.

I'm just stressed and over it all right now.

I mean.... would I not be ok replacing the damaged parts, pulling the oil pan, cleaning it out and then doing oil changes every 50-100 miles for 3 changes?

eh???

Bicycle Lee wrote:

I mean.... would I not be ok replacing the damaged parts, pulling the oil pan, cleaning it out and then doing oil changes every 50-100 miles for 3 changes?

eh???

I think the point they were making is it's possible the oil went low enough that it was running without oil pressure for a while, hence the scoring on the camshaft bearing surfaces.

IF that happened (don't know) then the main bearings and other things would have been starved for oil and would have damage as well.