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.
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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.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, 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 😂😂@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.
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.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'.
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.... you have 2 BENT Intake valves.
And you need to find out why/how they got bent.
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. HahaTaylorW,
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?
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.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
This is something that I was gonna' address.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?
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. 🤷🏻♀️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.
Ohhhh, interesting. And that would’ve been enough to bend the valves? Which, I guess the valves vs. theThis 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.
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.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.
might as well do the banjo mod too. look for "let the oil set you free, banjo mod". you could go 692 also.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!