Uh-oh!

Schwany · Jul 20, 2023

L.A.B. said:
None in 850 pistons.

Thanks

Figured as much about half an hour after posting that. Forgot to come back and edit the post. lol

Tornado · Jul 20, 2023

I feel for you Man! Had a similar experience passing a truck, on a hill. Gave her the beans so the trucker would see the power of the mighty Norton twin. All he got was a big puff of smoke and a good chuckle of watching me roll off road onto shoulder. For me it was as you initially thought, blown copper head gasket.

Deckard · Jul 20, 2023

It's all supposition until the barrel comes off. The fact that you have compression indicates the rod is still connected to the crank and piston pin. That's a lot of gap for a rod bearing failure. Very rare, but maybe a piston crown separation. That might explain the piston kissing the valve. That was only a known issue with early 750's, so kinda unlikely, but you never know..

Tornado · Jul 20, 2023

Perhaps he has a 355 degree crank ;-)

acotrel · Jul 20, 2023

Do not be disheartened - at least you did not get run over. Any crisis is an 'opportunity for improvement'. Just quietly take the motor apart and fix it. None of it is rocket science and 'life is a learning experience'. A bit of work is good for the soul.
Your mindset is important. Many people just want to ride their motorcycle and never work on it - so they buy Japanese motorcycles. After you have fixed your motor, your outlook on the world will be different - you will be competent.

cliffa · Jul 20, 2023

acotrel said:
Do not be disheartened - at least you did not get run over. Any crisis is an 'opportunity for improvement'. Just quietly take the motor apart and fix it. None of it is rocket science and 'life is a learning experience'. A bit of work is good for the soul.
Your mindset is important. Many people just want to ride their motorcycle and never work on it - so they buy Japanese motorcycles. After you have fixed your motor, your outlook on the world will be different - you will be competent.

Well said Al!

mean gene · Jul 20, 2023

Sorry to see. But about 8 bolts and the jug would be off, we're all waiting! Hope it's not as expensive as it looks.

Torontonian · Jul 20, 2023

I would use it as an opportunity .
J.S. C. Rods , Wiseco pistons .

Alan L · Jul 20, 2023

I’m sorry for your dramas but for goodness sake remove the dam barrels and put us (and yourself) out of our misery

Since we are all have a bit of a bet on it, my pick is a collapsed small end on the piston and/ or rod.
A broken crank is definitely a possibility but I can’t imagine it to be a slipper bearing with that much difference in piston height.
As others said, it would be far worse if you had of pressed on and ‘put a leg out of bed‘.
Anyway, we keenly look forward to the next instalment.
Good luck
alan

Fast Eddie · Jul 20, 2023

Larry, psychology is important here. The unknown is a big negative mental influence. The sooner you lift those barrels, the sooner your mind will start to look positively at what needs doing. You don’t need to fix it all immediately, just let your mind absorb what’s what.

The longer you leave it the worse it gets, so lift those barrels soon please.

KiwiShane · Jul 21, 2023

baz said:
Think of it as a great opportunity to build back better
At least it hasn't punched a hole through the cases

A mate years ago called me for a pick up one night...saying his bike made a rattling noise and said he hit the kill switch straight away...so hopefully it wouldn't be to bad....when we arrived to pick up his 883 to 1200 sportster kitted hardley...that night I discovered a rather large crankcase vent in the back of the engine case...if he had lost power from a bent valve like Larry did he may of been able to limit the damage...as you say...

concours · Jul 21, 2023

Larry, were you able to determine a cause to the failure last time? If so, what was it?

TWO bolts rattled loose, and sucked into both combustion chambers almost simultaneously?!

Saber · Jul 21, 2023

DennisMo said:
Bent con rod?
Dennis

This is my guess too.

baz · Jul 21, 2023

Saber said:
This is my guess too.

It'd have to be badly bent to lose that amount of height
And how would it bend?
Not saying it can't
I'm just on the edge of my seat to find out
Larry is a lot more patient than me
I wouldn't have gone to bed
Certainly wouldn't have slept until I'd pulled that barrel

Richard Tool · Jul 21, 2023

Valve train jumped time somehow ? Could the rod bend or crown separate / wrist pin bosses break from valve /piston collision?

kommando · Jul 21, 2023

All comes down to which inlet valve was involved the second time, if it was the same as the first blow up than that points to either the problem being oil supply to that valve (unlikely as there should be an oil seal on the inlet guide) or the cam follower is sticking up.

mean gene · Jul 21, 2023

The valve strike on that piston would not bend the rod. I'm betting wrist pin failure or piston failure. I've seen the big end of a rod fail and not do much damage, over extends the piston and strikes the valves. This failure picture did not bend the rod!

Onder · Jul 21, 2023

I figured by now there would be a 'go-fundme' page up to help with the overhaul.
But now, probably more likely time to assemble a flying squad to get over to his house to
pull that puppy apart. Yer killin' us on this! \

KiwiShane · Jul 21, 2023

On the plus side.. diagnoses of failure is far easier to determine on a engine thats reasonably still intact...and alot harder on one that has dropped its gutz all over the road...come in Larry ...do you recieve ?

Gilesy · Jul 21, 2023

Have you tried gently turning the engine over?

Uh-oh!

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