83 xj650 maxim broken cam shaft?

So I'll try and explain what I'm seeing and hopefully someone with a lot more knowledge than I will chime in and offer some insight.

I recently picked up this maxim that was having troubles starting or staying running, and of course the p.o. offers 'betcha dem carbs needs blown out n she'll perk right up', so I did some reading and found my way through the church of clean and after the hallelujah amen brother praise Jesus I reassembled and low and behold she purrs to life, sounding....clanky, but not knocky, it that makes any sense, here's where perhaps it was my mistake or maybe things were already screwed, anyways, I thought it sounded like the ticking was isolated in #2 cylinder but I wasn't sure, and since darn near every post I've read, which the list is considerable, valve clearance is priority number 1. ( I believe bigfitz is the local clearance nagger here, no offense intended, infact Im tempted to present myself to him for a sharp kick in the nuts for not heeding his diligent cautions) probably had I checked before firing up the ol gal things could of been different, anyways, pulled the plugs and in #2 looking down in there I could see what I'm assuming is the intake valve, it looks bent sideways and it jammed into the head where the spark plug threads bottom out, actually it looks as if that plug had blown out of the head and a helicoil had been installed, maybe not well, but first Im thinking maybe he threaded too deep and the valve caught the bottom of the plug and bent it, indeed the bottom of the plug had been broken sideways where the electrode and metal over tab are. So. Shit. Intake is moving up and down no where near sealing closed, valve and seal and probably guide would need to be replaced. Right? Well this leads me to better get the valve cover off and check clearance and scope things out. So cover comes.off and I immediately notice the Intake cam lobe down on #4 had broken, sheered, off the shaft. Like it was just flopping there on top of the shim. If I try and just fit the lobe back on the shaft what appears to have happened is there is zero clearance, so the lobe just tried spinning against the metal bucket or shim or whatever it js, sorry for my lack of knowledge here. I guess what I'm digging for is what could of caused this stuff. Could the two be related? The bike fires up and revs and the chain is tight and straight, like I would of never believed that cam shaft was broken until I saw it myself. I'm fairly mechanically inclined, not afraid to dive into something that i can fix myself, so long as a bunch of specialty tools or machine shop repairing is involved. What am I getting myself into? I feel like maybe it's not the end of the world and I can pull this off, but maybe I'm just yanking my chain and completely in over my head lol the more I think on it. The more I'm dreading what other damage could I find it I keep digging deeper. I know only so much can be done from afar but any thoughts or advise or perhaps troubleshooting steps for further diagnosis? I'm so used to being the guy that's fixing everyone's gear, but I'm maybe a little intimidated and franky quite bummed at the change in directions from "awesome I've got a new bike to fly' to 'ill be lucky if I get this thing on the road before next spring, if ever.

Thanks in advance,
David

 

Damn!
Any chance of uploading a picture or two of the cam, hellicoiled head etc.
Sounds insane... Might help you with some good answers.

 

Never heard of a camshaft failing in the manner you describe. Once you assess the extent of the damage you might be better and cheaper getting another engine.

 

I'll upload some pictures when I get back home. Maybe someone will spot something I missed.

 

Intake cam on #4
The view into spark plug hole on #2

 

You probably should get another head with cams , if you go this route replace the valve seals and lap the valves . Check the plug threads usually #2 and #3 that can get cross threaded . Get a new head gasket and you should be in business. Or as Franz said look for another engine. Just note your bike is a 650 maxim a 750 will swap in but a 750 seca mounts differently and the linkage for the shifter is different. Cheers

 

Yikes!... that head and cams are toast.
you own a 3 cylinder XJ.
I wonder what damage has been done to the piston if the valve has been stuck open also.
Bad news!

 

If the valve on 2 is damaged how did that happen if the cam timing is correct. Intake on 4 should will be closed all the time but that won't affect cam timing on the other valves. Can you set the engine to TDC and see if the cam timing is correct? Look at the cost of a replacement head and cams compared to a replacement engine. Might be better just getting the replacement engine.

 

Take the head and barrels off the engine before you buy any more parts.

 

Wow that is a first for me, never seen that before. I don't know if I would ever trust that head again, even if I fixed it? I would look for a good used one.

Getting a better look in those cylinders too. I would do a compression test once you pull all the bits out of the way. See if you have good compression, that is if the engine is turning over okay.

Again, that is a fist I have seen one bust in half so to speak...Wow.

 

The only time l have seen that kind of break is a Yamaha R1 crossplane crankshaft but l think it was raced.

 

Damn shame that's for sure.
Makes me think the rest of the engine would be in a pretty poor state if the PO let this happen.

So... How about just biting the bullet... Go above and beyond.
900 engine bs35/36 carbs 31a/58l TCI (whichever 900 engine you find) A bit of airbox alteration.
And damn...
You'll love that bike.

Just trying to be positive.

 

900 engine yes great idea. I think @Simmy is going to do that.

 

Thank You everyone for kind words and advice. Pretty bummed out but it's what I expected to hear lol. Love the community on here. You guys are all great. I'm pretty sure I'm looking for a new engine. This repair is just above my comfort zone. Maybe I'll keep it around just for practice.
Long days pleasant nights, ride on.

 

Strip it and rebuild it use it as a practice engine. You can set up the timing etc. Use the old gaskets. Or strip it and keep usable parts. Either way you learn more.

 

I meant his 900 turbo.

 

Well the cam never broke first. So that leaves the valve sticking, getting clobbered by the piston (it will be toast), and the cam hitting the follower every time it went around.
New head and probable barrels, but at least piston.

 

Wow, that is horrible, and due to the graphic content, is not suitable for all audiences.