Not what I was hoping to find. JBweld, where to from here?

[Seattle51]

Starting cleaning up the xs I just got home this week. Changed the oil, and started cleaning up the motor, it was pretty greasy. It looked like the left case gasket was shot and wheeping some oil, for years. And indeed, the gasket's pretty much shot.

What I was hoping that I wouldn't find after cleaning up 29 years of sludge is shown in the picture below. Looks like JB Weld to me... I'm curious where you guys would go from here? I haven't done a compression test yet, but I'm pretty confident its going to be ok. It runs great, doesn't smoke and leaks oil out of only that gasket (that I've found so far) How concerned would you guys be and what would you're next steps be if its yours?

I'm thinking;
1. Compression Test
2. If compression ok, leave it and move on
2a. If compression not ok, bang head into wall of garage

I'm not really sure what to think at this point I guess so any I would really appreciate your thoughts or ideas. How the hell would there be spots there that need JBweld???

 

[5twins]

The pic isn't showing?

 

[Seattle51]

Sorry, just added. I had arrows but the edit made the file too big. The big glob is on the bottom of the pic, the little one toward the top right.

 

[xjwmx]

Maybe the chain broke and got wound around in there and cracked the case. The oil in there is probably from the seal behind the drive sprocket. The nut there needs to be real tight or it will leak. The clutch rod seal looks like the original one, but it doesn't look wet.

How I would react to the JB depends on where I was with the bike. If it was brand new to me and I was all excited about it, I might look for new case halves. If only part of my energy was focused on it I might just stop the oil leak and forget about it. Practically speaking, if it isn't leaking from there, it's ok and may last a good while, or forever.

 

[5twins]

You're definitely going to need to remove some from the lower portion of the lower glob because it appears they've JBwelded your oil pan on, lol.

 

[sgallaty]

Hey man, don't knock jbweld. Many a cb750 rider has jbweld as a permanent engine component after the drive chain knocks a hole in the upper case.

Looks like they did a competent job, as far as jbweld goes.

 

[Seattle51]

I didn't think about the chain doing that. That sounds totally plausible. I'm excited about the bike, not so excited about a complete engine rebuild.

Whats the worst case scenario? 10 miles, 100 miles, 1000 miles or 10,000 miles down the road the jbweld gives way, and oil starts leaking out of that spot. THEN rebuild the motor? Can you see anything other than that happening?

 

[Seattle51]

I did see that there was perhaps a little "too much" jb weld...

 

[HeBme2]

Sounds like a Winter project! Ride the bike until it fails or you put it away for the season.

 

[XSLeo]

I just looked at two of my engines, one all apart and one with the left side cover off.
The small blob you see just ahead of the clutch push rod seal looks to be from the factory. It looks just like the two I looked at. It appears to seal the end of an oil passage.
The lower blob looks to be from being dropped while out of the frame. Wrong place to be from a chain break. The chain break will tangle around the clutch push rod and shift shaft.
If the JB WEld was done well it will never fail. Were it blobs over onto the sump plate if it is stuck to the plate then a hack saw blade carefully used will cut it free.
I would remove the sump plate and look up inside off the engine. If no structural bracing appears to be effected I would ignore it. Maybe smooth it down a bit and repaint it.
I just went out and looked at my lower case from the torn down engine. At that area of the case it is a flat smooth area on the inside, same as the out side. It has no undo stress on it as the engine operates. If the JB Weld don't leak then I wouldn't worry about it.
If thats all you find wrong then you can consider your self a lucky man.
Leo

 

[jmink427]

If it isn't leaking I wouldn't worry about it either.... but when or if I ever had to tear it down I would fire up the tig welder and weld that bit*h up! My cover on the left side is cracked that is what I am going to do to it. Tig weld it that is...

 

[Seattle51]

Thanks for checking on all of that for me XSLeo! When I get the motor out of the frame and on a stand, I'll take a look in there. What you said though is what I was hoping, that the weld was so low on the motor that there wouldn't be any structural or mechanical issues (most likely).

Thanks again!

 

[xjwmx]

The lower blob looks to be from being dropped while out of the frame. Wrong place to be from a chain break.

I thought it was a weird place for the chain to get to as well, but didn't think of an engine that had been dropped. Good deduction. Could also have gotten creamed there in a terrible wreck too, I suppose