The rear piston crown self destructed, and even partially came out the exhaust pipe.

The entire engine needs to be dis-assembled.

I can only imagine what was being pumped around the engine immediately prior to the failure.

Any new pistons would be impregnated with metal on start-up.

Rule # 1 of the bottom end still being good is that there has been no catastrophic internal engine failures.

 

We are in complete agreement on this. Here are pics of my cylinder head and piston after a failure ...




Here is what was found in the bottom end, and only after the crank was pressed out ...



Yes, complete dis-assembly, including pressing out the crank.

 

mick did you do the work yourself or sent it out

 

Generally, i do all of the dismantling and re-installing myself. I bring the cylinders and heads to my indie mechanic - he sends them out to his choice of machine shop and supervises that work.

Except for the bottom end. I removed the clutch, trans, cams, etc and gave him the remaining lump to separate the cases, clean, inspect, and put back together. I also let him re-install the trans and clutch.

It seems to me that it is not "economically wise" to pay $70 [or whatever] per hour for the unbolting and bolting on of parts - at least not at my level of "economics". However, for the intricate work i am willing to pay.

I do not have any formal training in shop practices, shop tools, precison work, etc. I see guys on these forums who took shop in high school, worked on bikes back in the day, and learned from their dads. I do not have any of that, just what i have learned working on my own over the past several years, and from these forums.

 

I have seen a few heads come off valves in Ironheads before.
But the best I ever saw was a 60s model xl, where the piston had destroyed itself into no less than at least 500 individual pieces(this was about 15 years ago now). I bagged it all up for the owner.
He did comment that it had been a bit noisy for the previous few days.
He had a short in the genny, so that every time he revved it over 2000 rpm, it gave him an electric shock through the clutch lever, causing him to constantly stall the bike(as he let go quick).
Totally hilarious.
I did not learn anything mechanical from my dad, as he was not that way inclined.
I did not do "shop" at school, as there was no such thing.
I did start working on bikes as I owned them, out of interest.
I have received formal training.
I have been working on HD and the like for 30 years.

 

There is also tricks of tearing the motor apart sometimes the manual don't tell everything there is thats what I am afraid of. I would like to tear one down and get it running again

 

It doesn't look very good... The kickers stuck to which really concerns me although slightly less than taking the bottom end apart by myself does. Don't have much choice though. Pretty sure the heads are ganna be fine after some machining and valve lapping (I 'assume' they already will need be machined to accommodate the new pistons anyway?) The valve stems are straight and look okay far as I can tell and so do the valve springs. Still need to confirm that though and check the spec's. Hopefully the machinist will be able to help me with that!

 

I do not have the knowledge and experience to comment on this much; but i believe dismantling the bottom end you can do but the crank does need to be pressed out of the [right i think] case half. Then i believe it is a specialized task to re-assemble.

 

You need to have that engine completely dis-assembled.
There is not one part in it that could be run again without AT LEAST the type of cleaning that only full dis-assembly can allow.

Actually, the crank is captive in the left case.

That is a reasonable effort you have there.
Not the best I have seen, but, without any doubt, a strong contender for second prize.

All those scores are missing alloy, which has turned into a paste, and is currently living in places like your lifter wheels, and from that type of part ....... IT CAN NEVER BE CLEANED OUT AGAIN.
If you try to run those parts after washing, the metal will just keep coming out, and embed itself in the piston skirt, and then........ HERE WE GO AGAIN!!!!!!!!!!

Your comment regarding machining heads and new pistons, kinda tells me you are not particularly mechanically inclined.

AND THAT IS TOTALLY OK.

Despite this, you can still do much to help yourself.

First thing......... POOR MAN PAYS TWICE(at the very least).

Do not worry about the kicker for now. That is the least of your concerns. That will all come clear in due course. When an engine is violently seized, you would hardly expect the kicker to turn it over, and any other issues will be hopefully minor(unless you have broken the cases in half as well, so might be best you take the kicker cover off and have a little look-see. And yes, sad to say that would be quite common).

You have to decide. Am I going to tool up and learn???? Am I interested in that?? Can I afford that?? Can I actually achieve that??

Once that decision is made, a way forward can be devised.

 

how does something like this happen to a motor