Need a fix please,...

73TX650Twins

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.. for cracks at this stud bolt on bottom of case. The stud is actually loose. Any ideas appreciated.

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This situation comes to light every so often. Try a search on it. Lower case cracking? Low temp welding welding with those rods seen on amazon / ebay?
 
If it’s not leaking leave it alone until the engine is out of the frame, put a nut and washer on it but only nip it up. Looks like it’s hit the floor at some time judging by the backside of the hole being cracked.
 
Speaking in general terms ..there are many things in this world that has cracks and still are used.
It comes down to if these cracks can make the object unusable or dangerous
In this case sealing and load carrying..
And if the crack is propagating .. getting larger .
I am with Rasputin it looks as it has taken a hit or / and been over tightened
Again in general terms a small surface crack does not make a big job necessary .
And on he other hand a crack that runs all the way through does.
These look rather large to me .
It involves a lot of work taking it all apart to replace or perhaps weld. or something like that.
There are people out there who welds aluminum an expert on that can make an assessment on if it is is possible
in this case. Without tear down.
The decision depends on many aspects.Status of the bike future plans cost time own interest and competence.
I Would suppose a replacement casing would be cheaper and simpler if a tear down is needed.
My first guess at this point in time if not leaking .. Smear on some Chemical do you call i JB Weld
Dont tight it fully
Drive a while see what happens. It might work
 
Thank you for the replies. Yes, assuming the crown nut must have taken a hard hit at some point to do the damage. I do have the engine out of the frame but really do not want to do a teardown and replace lower case. This beauty had leaks at typical culprit seals but I cannot say for sure if it was leaking at this stud or not? Suppose it's safe to assume it was.

All typical culprit seals have been replaced and I didn't do a close inspection on this until I had motor laid on its side ready to drop the frame over it.

Should have looked a little more closely early on. :doh: Figured crown nut had just worked loose and fell off and that I would just pop a new crown nut (with blue thread locker) and copper washer and be done with it. Thinking I might try a redneck fix like the one shown below,... clean/degrease around the stud and use a syringe to inject some JB Weld in the gaps/cracks. Let it cure and spin on a new crown nut and snug it up and hope for the best.
Please tell me if that's a huge mistake?

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The stud is actually loose.
The loose stud could be of concern. It could mean the upper case is cracked also.
I think I would double nut the stud and see if it will tighten up. If it does put on a new nut and washer snug down, blue loctite if you want. If the stud will not tighten then you have a decision to make. It doesn't look like it's been leaking. I personally would not use JB Weld. I don't think it would do much good there. Plus if you ever go to have it welded it would all have to be cleaned out.
 
JB Weld is some amazing stuff. That would my goto in this situation.

Will have to remember the door latch tech.
 
Thanks. Will double nut it and see if I can snug stud back up into the case. I have not been able to find a good pic or parts fiche of this stud and how it fits in the case,.. does anyone have an image of this? Since the stud wiggles back and forth a little I'm not very hopeful. Almost puked when I noticed it. Thinking I might be going with the JB redneck patch up fix regardless. I have had good luck with that stuff in the past.

I tried a search about this problem but its a hard one to find info on, I'm sure it's been talked about on this forum and been done before. Amazing group of folks on here with a wealth of knowledge. Thanks again for the help and suggestions. Will post a follow-up and let you know how it goes.
 
Hmm, lets see what those two studs do....
studs bottom.jpg studs.jpg
Well, that seems to be a pretty important job.
The good news is that it's unlikely the stud itself is loose in the top case.
Cracks look well aged, dirt filled,not oily so it's prolly stable.
I might be thinking of some sort of cupped washer to keep the cracked bits from spreading as the nut is tightened.
Maybe smear on some hylomar or other non hardening sealant, then use a regular nut rather than a dome nut so you can watch that you aren't pulling out the stud as you tighten it and it's twin to the correct spec. and go on with your business.
 
For the cup washer.
Start with a regular old flat washer, bolt it into a 3/8 socket of the appropriate size, clamp the socket atop a vice and carefully hammer the edge down around the socket to form the cup?
 
Thanks for pics Gary but you made me puke again. You mean it's only holding the crank in? I was hoping those fancy chrome crown nuts were down there under then engine in the dirtiest part of the bike just to add a little glamour. Yeah baby. :hump:
If it was Harley I'd be worried about it but this is a very well engineered 70's era Yammerhammer. Bulletproof. :gun:
 
Honestly cant say if it was leaking right there or not,.. this thing marked it's territory everywhere we went but only right after it was parked. Didn't seem to drip continually which I would think might occur there. Thought pushrod seal and countershaft seal / sprocket spacer interface were main culprits. Those have been fixed hopefully. Thanks to the infamous Mailman BTW and his tutorial(s).
 
PS further thought on making a cup washer. As above, then heat it red with a torch, use a larger 1/2" drive socket or piece of pipe to drive down the edge forming a nice neat cup. :sneaky:
Did you know that XS650s shake? Guess where all of the out of balance mass swinging around transfers it's energy to the rest of the bike? But seriously yeah it should be fine if you aren't contesting a half mile against Kenny!
 
update...
Double nutted and confirmed the stud is firmly seated / tight in upper case. That’s a relief.
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Was thinking Gary’s cup washer would be perfect solution so I set out to determine size of washer needed and then I noticed there really isn’t much of a lip to capture in the cup. The casting seam of the case looks like it will interfere?
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Pulled crown nut off adjacent stud and noticed that both of these must have been loose and rattling around for a long time. Check out how bad both holes are worn...
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Decided to inject JB Weld into the gaps... will let it cure for a couple days and install new copper washers and crown nuts with some blue thread lock. Hope it works. :bike:
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