Topic: I think I blew my oil pump at 75mph, Pre case split findings, with gory pics?

[manjisann]

So at this point I'm wondering what happened first? Also, what would have caused this to happen? I set the valves less than 1k miles ago.

Thoughts?

Brandon

[Frankenkit]

did I get that one pic right, where it looks like you lost the valve retainer?

[fantino]

That piston will make a pretty epic paperweight, eh?

Truly some gnarly wreckage you have on your hands there.

[manjisann]

Kit, yup, the valve retainer had snapped off. When I first pulled it apart it was where it was supposed to be but when I touched it, it fell off.

Fantino, not much of a paperweight anymore, it lost most of its mass 

Brandon

[fantino]

True enough. I can't really tell from the pics, how did the conrod fare?

[scottly]

Looks to me like the head of the exhaust valve snapped off, then the retainer simply fell off due to lack of spring tension to wedge it in.  

[paulages]

wow, that's amazing.

my machinist friend Dan Hall, who helped with R&D when building my 718 engine, had a glory/shame shelf in the front of his shop with lots of melted pistons and valves embedded in pistons crowns, etc. my favorite has a flat top chevy piston with a valve stem lodged upside down in the top of the piston. he had come back from the korean war and started racing and building hot rod engines, and became obsessed with building the fastest engines he could. he said he was drag racing, and about a third of the way down the 1/4 mile strip the engine locked up and he bounced the rear end through the traps at over 100 MPH and still beat the other guy... on piston went straight through the floorboard and lodged itself in the asphalt. that's the one from the case. they never found the other one.

[florence]

I had a similar thing on a different bike.  Unknown to me, the valve had been hitting the piston and eventually snapped off like yours, destroying the engine.  Do you think you may have done your valve clearances incorrectly?

[CBJoe]

 

I really hope that your going to hang a few of those pieces as trophies!

Joe

[Frankencake]

Well now you and Jerry have matching wedding rings.
I see what did in your piston but what cracked the case?  You have your work cut out for you, Sherlock.  Your are going to keep all of the broken bits right?  I have my phalic-shape-bent connecting rod from the Enfield hanging on the wall.

[wrenchmuch]

Its hard to belive it kept running in that condition . The valve stem broke at the retainer ? I'm sorry it happened . Hope you can salvage some parts from it . Bet a valve bit holed the case .

[ekpent]

Couple new rings, a little dab of JB Weld, and you'll be back on the road soon 

[Trav-i]

WOW!  I guess if your gonna do something like that do it big.   It looks a lot like that CAT engine did when I got into it.  At least in your case you had a spare engine, and won't have to spend $12,000 to rebuild it like that guy did. 

[Soos]

Hey Brandon, I got a set of cylinders I would trade for the ones you got.
My next overbore is going to get new sleeves anyway.


That will be quite the conversation piece I would imagine.




How does the conn rod look? I have a stocker set for cheap if you need them.






l8r

[manjisann]

The conrod is pretty beat up and I won't be using it again. I'm wondering whether the crank is any good anymore, but I won't know for sure till I get her apart. The other conrods looked ok, as did the other pistons. Aside from the one sleeve, the the cylinders are in good condition. The head is obviously shot. I'm wondering what the clutch, transmission and final drive is going to look like.

I'm suspecting the ticking noise I was hearing was the valve stem or something smacking the piston. I still find it super hard to believe the bike was running as well as it was with one cylinder not operating correctly.

As for cause, I don't believe it was a valve adjustment issue, at least not from me adjusting them wrong. It's possible the nut backed off on the rocker and allowed it to go wonky I suppose.

Soos, PM sent.

Brandon

[Frankenkit]

fwiw, I actually had one of the adjustment studs (the threaded bit the locknut goes on) snap off, the nut got 'lost' around the cam, etc.  Bad times.  Just so you know it's possible.  Not great, but possible.

[manjisann]

Yeah, I know it's possible. Unfortunately I don't think I'll ever really know for sure what the first domino in the chain was, or when the valve snapped off. I'm pretty sure I know when the hole got punched into the piston though, and I DEFINATELY know when the hole was punched in the crank case 

Brandon

[RAFster122s]

If you want a paperweight I would suggest get someone to embed it in a casting resin so you will have a smooth object you can marvel about...
A neat casting of it would fill the center and be cast flush with the ends so they were square and  the diameter be that of the piston so you have the ends protected in resin and you can still handle and touch the piston sides.

David

[750goes]

"pharque" what a mess,

amazing it  didn't lock up on you.....

nice photos - should go into the gallery.....

[Hush]

See I told you....these bikes will pull just as hard on three cylinders.
As long as the conrod snaps nice and clean you are good to go to get home.
That mess looks like that trail bike I was inspecting for a young fellah a few weeks back, same deal, inlet valve snapped and fell on piston which pummelled it into oblivion.

[greasy j]

yikes!

[manjisann]

Insert Quote
"pharque" what a mess,

amazing it  didn't lock up on you.....

nice photos - should go into the gallery.....

Yeah, I'm REAL happy it didn't lock up on me 

Hush, the crazy thing is, it's the exhaust valve that snapped, and yet all those bitty pieces went into the inlet side??? Bit of a headscratcher for me.

If you want a paperweight I would suggest get someone to embed it in a casting resin so you will have a smooth object you can marvel about...
A neat casting of it would fill the center and be cast flush with the ends so they were square and  the diameter be that of the piston so you have the ends protected in resin and you can still handle and touch the piston sides.

David

I may actually do that, sounds like a cool idea. Heck I might even try doing it myself

So the camshaft was grooved pretty badly around the lobe end, can that be welded up and reground to spec? If so, does anyone know what something like that might run? I have a feeling that rebuilding this will cost more than just buying a known running engine, but I've sorta wanted to tear one down to the nuts and bolts and rebuild it, and now I have a darn good excuse too. Besides, I have some modified 750 pistons from Soos that I'll get to stick in it, so even more of an excuse. So any excess money will just have to get thought of as tuition to the school of DIY motorcycle mechanics.

Brandon

[scunny]

yes the lobe can be built up and reground, don't kmow your rates tho.
probably get a used one cheaper. whats the cam bearing surfaces like in the head and cam cover ?

[Jerry Rxman Griffin aka MuthaF'er]

Geez, that looks familiar except mine was the intake. Abuse was my culprit. Missed power shift to 2nd. Tach went ballistic. BAM! I pulled the clutch immediately but it still rotated a million times at least  No locked rear tire. Stronger valve springs have helped since. Don't forget to tear your oil pump apart and get those tiny bits of compressed aluminum out that you will find. It's amazing how easily the rotor will squish them onto the sides. I was offered $500 (paid $1800 for it new) by the guy that took it apart for a 1+ year old parts bike that needed an expensive new engine or probably more to have him repair it. 

[Hush]

Hmm maybe it dropped the exhaust valve as the piston went down then on the up stroke the inlet opened and some shrapnel got drawn in that way?
Anyhow I'd like to know how much crap is lodged in the exhaust pipe its self!