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Hasn't someone made an alluminum shield to protect that area? I seem to remember seeing something…
 

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Discussion Starter #63
Typically, we have seen burn through effects on the bottom side of the airbox. The standard exhaust system has the header pipe connecting to the muffler almost directly under the airbox. There is a fiber gasket to seal this junction, and any leakage of hot exhaust gases past the fiber gasket that seals the header to muffler, would allow gases to threaten the integrity of the airbox. If that opens up, then dirty, unfiltered air gets sucked into the engine, and ruins the cylinder/piston sealing process.

Pic here showing the underside of airbox; note how heat has allowed the plastic to be pulled inward due to the vacuum effect from engine suck.

In this pic, the allen bolt exhaust pipe clamp appears to still be in-place. The possible burn-thru area is in-front & above the clamp. Also the clean side air box drain hose must have a Cap on it to prevent dust ingestion. Dust ingestion could have caused your oil burning and could cause valve and valve seat wear. Which is why we look & test. I use brake clean, carb clean or gasoiline in the ports to hydro-test valve sealing, rather than water. Usually only takes seconds to see good or bad.
yes, in that photo the exhaust was still on, but have since taken it off and no melting on the air filter. However, what I’m assuming is the clean side drain hose in this photo seems to be in pretty bad shape, and definitely no cap.
My next morning off I will finish pulling the head off and do the test on valves to make sure they are seating/sealing properly.
@TaylorW,

I took this to mean that the gasket that goes between the head and the exhaust header was missing. This is unlikely, as it would have hissed and spit and made loud and raucous noises when you closed the throttle. What you would be looking for would be a rounded rectangle of squished copper (that is probably sooted to black) that may be adhered to the head or header.

To Paul's point, a head gasket is certainly not missing.
yes, definitely not the head gasket, otherwise I’m sure that would’ve been leaking oil and I would’ve actually checked the level and avoided all this 😂😂
 

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Discussion Starter #64
And just for anyone else who may stumble upon this thread and be curious of what it might cost to send to Engine Dynamics, here is what they quoted me:

“Cam journal repair, one side only $250.00 plus 2 bushings used in the repair at $25.00 each.

Valve job & assembly $304.00 plus new seals at $5.25 each. Guides & valves would be checked but not replaced unless necessary.

Shim adjust to OEM specs $68.00 plus $15.00 per shim if required.

Bore & hone for a Schnitz 685 kit $135.00. Please supply kit with job.”

obviously it must be noted that every repair quote may be different based on amount of damage, and my actual end cost may vary. But honestly, these prices seem extremely reasonable. I was prepsaring to be queazy when I received the quote because everyone was saying they were super expensive. But considering the local kawi shop was gonna charge me $500 just to crack the engine and diagnose, these prices were Pretty easy to stomach.
 

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Discussion Starter #65 (Edited)
Alright, it’s been a busy couple weeks, but I finally got the head fully pulled off. Now I’m no engine genius, but I’d say I have 2 toasted valves
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don’t know if anything can be gathered from the top of the piston, but here’s that.
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at this point, do I still get this head repaired, or try to get a full new/used one with valves? Or just get Engine Dynamics to replace those two bad valves? I’ve been working a lot lately to scrounge up some extra cash for this repair and want to do what’s best for the bike in the long run. but At this point I’m not sure what would be better, repair this head or get a new one?

gonna try and get the cylinder off today as well to check the piston rod and main bearing
 

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Discussion Starter #66
Got the cylinder off and the piston is in good shape and no play in the piston rod. Piston rings are worn and fit sloppy in the cylinder, as suspected. Had a friend stop by and look at it and noticed slop/play in the cam chain and surmised it may have jumped, causing the two intake valves to bend? Seem plausible? I guess my next free day I’ll try to pull the left side off and look at the doohickey and lower end of the cam chain.
 

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I was gonna' suggest that you have 2 BENT Intake valves, not 'toasted'.
And you need to find out why/how they got bent.

You and your friend are on the 'right track'.
 

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Discussion Starter #68
I was gonna' suggest that you have 2 BENT Intake valves, not 'toasted'.
And you need to find out why/how they got bent.

You and your friend are on the 'right track'.
So in the meantime, while I try and figure out what caused the valves to bend and check out the cam chain, I’m really trying to decide whether I should still try and fix this head, or just grab a different one, because now we’re looking at around $600+ for repairs from Engine Dynamics, not including the 685 bore and shipping, and whatever repair/replacement is necessary to fix the valve-bending problem, which would probably take me to well over what I’d like to spend. I already preemptively ordered the piston kit, but am contemplating returning it and just getting this head: Kawasaki KLR 650 Cylinder Head Base Valves Springs 11008-1297 97-07 | eBay and doing the bore at a later date when more money is available.
thoughts? Is it still worth repairing this head, or maybe better grabbing a used head off eBay?
 

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TaylorW,
It was the cylinder & piston & rings that allowed/caused the cylinder head cam bearings to be damaged!
Surely you do Not want to risk damaging either a repaired head or a replacement head, do you?
 
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... you have 2 BENT Intake valves.
And you need to find out why/how they got bent.
I suspect the intake camshaft locked up, owing to absence of lubrication. The highway speed provided sufficient force for the crankshaft to "jump" the valve train chain and push the piston into the open intake valves, hence the bent valves and corresponding witness marks on the piston.

Jason
 

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Discussion Starter #71
TaylorW,
It was the cylinder & piston & rings that allowed/caused the cylinder head cam bearings to be damaged!
Surely you do Not want to risk damaging either a repaired head or a replacement head, do you?
Yea no, absolutely not. just simply stuck between trying not to spend all my savings on this repair and wanting to do it right so it doesn’t give me much trouble in the future. Delicate balance. Haha
 

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Discussion Starter #72
I suspect the intake camshaft locked up, owing to absence of lubrication. The highway speed provided sufficient force for the crankshaft to "jump" the valve train chain and push the piston into the open intake valves, hence the bent valves and corresponding witness marks on the piston.

Jason
Ah okay thank you for that simple explanation. I was curious if this was all related, or if the bent valves were a totally different issue that was there even before the cams seized. With the valve chain being “jumped”, would there have been noticeable performance differences on that last highway drive and then my last 1/4 when it seized? having only ridden the bike for 3 weeks before all this happened, I definitely wasn’t tuned in enough with the bike to notice small performance differences as “abnormal” at the time, but looking back, can say there was definitely sluggishness and increased engine vibration those last rides.
 

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One other option would be to keep an eye peeled for a complete drop in engine... Sometimes you can score one for a decent price, the only catch 22 is that you don't really know the condition of the replacement engine unless you get a really honest seller.
 

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With the valve chain being “jumped”, would there have been noticeable performance differences on that last highway drive and then my last 1/4 when it seized?
This is something that I was gonna' address.
I do not believe that the cam chain jumped timing on the sprockets.

I Believe that when the camshaft seized in the cam bearings the small steel Locator Pin under the head of the Sprocket Bolt Broke, allowing the sprocket to twist on the camshaft.
 
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Discussion Starter #75
One other option would be to keep an eye peeled for a complete drop in engine... Sometimes you can score one for a decent price, the only catch 22 is that you don't really know the condition of the replacement engine unless you get a really honest seller.
I had considered this, but the whole “hit and miss” idea of grabbing an entire engine off eBay just seemed a little too high. Plus, I figure this way I’ll at least get to know my engine really well for any other maintenance in the future. 🤷🏻‍♀️
 

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Discussion Starter #76
This is something that I was gonna' address.
I do not believe that the cam chain jumped timing on the sprockets.

I Believe that when the camshaft seized in the cam bearings the small steel Locator Pin under the head of the Sprocket Bolt Broke, allowing the sprocket to twist on the camshaft.
Ohhhh, interesting. And that would’ve been enough to bend the valves? Which, I guess the valves vs. the
piston wouldn’t take much to bend them. I’ve been putting off pulling the rotor to check the lower cam chain, doohickey, and anything else down there because of needing the rotor holder/wrench. Any cheaper way than buying the special tool? Otherwise I guess I’ll probably just drop the money on the Eagle Mike complete doo kit and get that done while I’m in there.

Also, finally got the head, cylinder, and piston kit sent of to Engine Dynamics, so hopefully I can get this whole cam chain issue figured out before the top end comes back
 

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I do not believe that the cam chain jumped timing on the sprockets.

I Believe that when the camshaft seized in the cam bearings the small steel Locator Pin under the head of the Sprocket Bolt Broke, allowing the sprocket to twist on the camshaft.
Whether the chain jumped or the locator pin sheared the result is the same: the valves became out-of-time and collided with the piston.

Jason
 

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@TaylorW, let's hope @pdwestman is correct and the pin sheared. There is less likelihood of damage to the cam chain sprocket on the crank, the cam sprockets, and the cam chain itself. You should have a look-see to see what's going on there. I'm not sure what part of the cam train is supposed to be sacrificial in the event of a 'negative clearance event'; that is, if the pin is supposed to shear or if the cam chain tensioner is supposed to blow. I don't think that KHI planned for an exhaust cam siezure, but effectively it acts similarly to a negative clearance event.

Here's a discussion of removing the cam gear screw, which is a bit of a sumbtich to get loose due to the size of the flange on the screw head and the whole tube of thread locker the factory puts on each screw's threads.

Read through posts # 169-172: Show me your Tool

If you are going to need cam parts, I think I have some extras, though I am not sure if I have an exhaust cam with a KACR on it. I would have to go into the Shed of Horrors and look. I think I could scavenge pins and cam sprockets. I
 

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Yep, that was it. I just took the cam chain guard off and cams out, so just the tension from the cam chain. I'm learning! haha. Appreciate the clarification!

The consensus seems to be the Engine Dynamics/685 route, especially if that will get me to reduce oil consumption. And then, either way, I may pay you a visit at Lander Marine to look into the oil system mods, since I live just 3 hours north, and I might as well get her using oil as efficiently as possible!
might as well do the banjo mod too. look for "let the oil set you free, banjo mod". you could go 692 also.
 

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I would just use 2 pieces of wood in the jaws of a bench vise to clamp the LH camshaft lobe (camshaft vertical in vice) to allow loosening / removal of the sprocket bolt.

But I did admire Toms cam sprocket holder the first time I saw it. But with a sheared locator pin, even Tom would have to resort to wood blocks (or soft jaws) & a bench vise. :)
 
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