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MOTOBRICK MARKETPLACE => NM ~ Not Mine - Just Compeled To Post It Up => Topic started by: zipster68 on August 08, 2016, 01:09:40 PM
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Just bought this 1985 naked K100. Then I noticed this. Looks it has suffered a low speed drop due to some plastic wear on the LH turn signals. So, is this the kiss of death? Could I have this welded. Ride as is?
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That part of the broken bolt shaft is unthreaded, so the missing piece was only maintaining compression pressure between the bolt and engine block to hold the cylinder head on. The missing piece reduces the available area for maintaining compression thus putting more stress on what remains.
I would not do too much riding with it the way it is, as it will overly stress what remains of the bolt shaft compression points and compromise the cylinder head seal. A good welding job should help redistribute the pressure stress to what it was.
The good news is that it looks like the cylinder head seal is still intact.
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Thanks. I thought that was a mounting point for engine to frame. Didn't realize that was head mount to block.
-Ray
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Look at it again. Pretty sure that mounts engine to frame. See pic, it's the top left bolt flange.
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Sorry, you're right. So the cylinder head thing is not a factor, but the strength of the attachment point still is. I'd try a weld first.
Nice valve cover.
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You also might be able to get a second hand head, price both and see.
Regards Martin.
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that casting is the block
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that casting is the block
I do believe we're looking at damage right at the tip of the arrow in the attached diagram.
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Ah, thanks. So that's replaceable.
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Replace it or weld it either way the head will have to come off. A good time to check valve clearances, cam chain and tensioners. This will give you an idea of which way to go.
Regards Martin.
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Er hem,I have inadvertently riden Over 6000km with my other one(op side) simply missing.I was touring.I did not notice any handling issues....Ye haah.
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JB weld!
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Really not sure what to do. I'm pretty sure that replacing the head is beyond my capability as a mechanic. I'm also pretty sure that welding that flange up in place will destroy the head. I'm also pretty sure that those frame points are load bearing and essential. Any ideas before I declare this a loss? Or is the remaining amount of aluminum meat enough to hold it together?
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I'm pretty sure that replacing the head is beyond my capability as a mechanic. I'm also pretty sure that welding that flange up in place will destroy the head. I'm also pretty sure that those frame points are load bearing and essential. Any ideas before I declare this a loss? Or is the remaining amount of aluminum meat enough to hold it together?
First, I want to observe that aluminum meat is a product destined for failure.
You've got options.
Do what Chaos suggests and be inspired by the Dude; but don't use the bike as a scrambler. Enjoy riding it in free air. I'm guessing that many here will never feel the need to swap an engine or even remove a cylinder head. You might be one of those; the JB Weld may be good enough, this engine may be good enough and a crack in its repair will show eventually show. Decide then. It's currently not a "track day" bike.
Ride the bike to several welders and show them the problem. Listen closely, compare what they say then decide.
If it appears that this bike is likely to require a lot of bucks to be roadworthy, just say "Feck it", sell it for whatever you can get and mark it off as a lesson learned; however, you be the one to show prospective buyers this defect. I made a couple of bad vehicle purchases early on when I knew nothing about engines, drivelines, brakes and body rot. You eventually learn about what you need to inspect and what you need to ask when buying used; otherwise, you buy from somebody with an enforceable warranty, or you buy new stock.
Someone will buy it and, if the rest of the bike is decent enough, maybe will install a reconditioned head on it then ride it to Tierra del Fuego; maybe even go there regardless of repair if they're desperate enough.
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Really not sure what to do. I'm pretty sure that replacing the head is beyond my capability as a mechanic. I'm also pretty sure that welding that flange up in place will destroy the head. I'm also pretty sure that those frame points are load bearing and essential. Any ideas before I declare this a loss? Or is the remaining amount of aluminum meat enough to hold it together?
It looks bad.but..how did it get there? Is there a complimentary bit of damage somewhere else that gave it the shove in the first place?Here may be your answer about safeness.
When I discovered my missing bolt I just thought I forgot to put it back last time....I just put it back and thought phew,I'm a twat but a lucky one.Before I discovered this missing bolt,I rode it like I stole it.
I think it's ridable and faced with the options,I'd just ride it and watch that area regularly.Afterall,there is plenty of meat for normal use,just not luck pushing crash diving stuff.The bolt threads into the frame lug.Pull it out and check the remaining aluminium is sound before riding off with a measure of confidence.
I hear Tierra del Fuego is the place to go for the ultimate test ride.
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Thanks Laitch and Dude for the sage advice. I thought the JB Weld comment was a joke, but if it's 50% as strong as aluminum, that's better than nothing.
-Ray
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Thanks Laitch and Dude for the sage advice. I thought the JB Weld comment was a joke, but if it's 50% as strong as aluminum, that's better than nothing.
-Ray
It doesn't take the place of aluminum meat, but it spreads better.
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JB weld,Good for hiding it but...I'd want full disclosure.Need to watch for "developments".
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posting in hopes of learning what option was chosen for this K head problem.
Curious as to what u decided to do about it.
Changing the head would be my choice.
All the other items listed to be done while head is being replaced are necessary maintenance anyway.
Vroom,
Troy