Author Topic: Case Crack?? (Read 1576 times)

BrickWoll · « **on:** May 09, 2021, 05:01:29 pm »

Hey All. I am in the final stages of a long winter rebuild on my '77 CB550. When fitting my oil pan back on after cleaning, I noticed what looks (and feels) like a crack just above the seam where the pan fastens to the case. Can anyone confirm if this 11th hour reveal is as bad as I think it is? Shot is from rear-left toward front of bike.

Any info is appreciated.

minimo · « **Reply #1 on:** May 09, 2021, 06:09:57 pm »

Ouch. That sucks and I’m sorry to read about this.
From my personal experience dealing with repairing cast aluminum parts like on the engine, in most cases it’s easiest to find a replacement part; if you’re lucky to find them.
Repairing this sort of thing involves tearing everything down and being meticulous with the preparation, as in copious amounts of cleaning and blasting of surfaces (and repeating 10x) to ensure a clean slate to work from. If the cast aluminum is not prepped well, the impurities can promote porosity on the welds and you end up with more of a headache trying to fill in a bunch of pin-holes which is the last thing you want in an area where oil leaks are likely to build up the most.
Skilled welders will know what they’re up against. There’s a general fear and mixed notes from folks surrounding the warping of metals when welding, and it’s usually because they don’t evenly heat up or bake the parts before they begin welding, otherwise the metal can contract in a not-so-great way.
There’s also the clean up after the welds. Because there are mating surfaces here, you’ll want to spend some time honing them flat and as straight as possible by placing a straightedge on the area as you grind. A thicker oil pan gasket will also help :-)
But fear not. A fix for this is possible - I’ve certainly seen and experienced worse. Just don’t put JB Weld on it and expect to walk away as some folks have done.
Good luck!

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minimo · « **Reply #2 on:** May 09, 2021, 06:15:10 pm »

BUT, before tearing it all apart again, since you’re seemingly unclear as to whether this is an actual crack or a casting mark, perhaps you should clean the area very well with some degreaser and wipe it all down, CLEAN, and go out for some length of rides. Check the area and clean again. Repeat all of this until you are certain that there is some leak coming from the “crack.”
Another helpful tip after cleaning is to apply some baby powder around the area to make a source of leak more visible.

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calj737 · « **Reply #3 on:** May 09, 2021, 06:23:28 pm »

Crack. Plain and simple. After thoroughly cleaning it, hit it with a propane torch. That will help show you the length of it.

It can be welded, but it won’t be fun. Motor out of the frame. Oil drained. Whoever welds it will clean it repeatedly, grind the crack open, then spend a good while welding it closed and dealing with all kinds of crap. Don’t expect it to look great, but where it’s located, it will be fine. Leave the pan on, remove the seal when welding it. Unless the crack extends all the way to that surface. Then some light filing will make the mating surfaces flat again.

BrickWoll · « **Reply #4 on:** May 09, 2021, 06:27:12 pm »

Quote from: minimo on May 09, 2021, 06:15:10 pm

BUT, before tearing it all apart again, since you’re seemingly unclear as to whether this is an actual crack or a casting mark, perhaps you should clean the area very well with some degreaser and wipe it all down, CLEAN, and go out for some length of rides. Check the area and clean again. Repeat all of this until you are certain that there is some leak coming from the “crack.”
Another helpful tip after cleaning is to apply some baby powder around the area to make a source of leak more visible.

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Thanks for the advice minimo. I will clean it up and watch for seepage for before any drastic measures are taken. I've put far too many hours and $ to NOT exhaust every possibility before welding or *ugh* engine swap.

BrickWoll · « **Reply #5 on:** May 09, 2021, 06:37:54 pm »

Quote from: calj737 on May 09, 2021, 06:23:28 pm

Crack. Plain and simple. After thoroughly cleaning it, hit it with a propane torch. That will help show you the length of it.

It can be welded, but it won’t be fun. Motor out of the frame. Oil drained. Whoever welds it will clean it repeatedly, grind the crack open, then spend a good while welding it closed and dealing with all kinds of crap. Don’t expect it to look great, but where it’s located, it will be fine. Leave the pan on, remove the seal when welding it. Unless the crack extends all the way to that surface. Then some light filing will make the mating surfaces flat again.

Thanks for the info, calj737. Going to start with a thorough cleaning to get a better idea of what I'm dealing with. If it comes to welding, can this be addressed from the outside only or will the case need to be opened? My welding knowledge is exactly none.

754 · « **Reply #6 on:** May 09, 2021, 06:38:13 pm »

If it is a casting flaw , its sticking out... if its an innie, it is a crack

BrickWoll · « **Reply #7 on:** May 09, 2021, 09:15:14 pm »

Quote from: 754 on May 09, 2021, 06:38:13 pm

If it is a casting flaw , its sticking out... if its an innie, it is a crack

This gives me a bit of hope because there is a distinct ridge between the two sides when I run my finger across, but the two sides are not on the same plane which seems like a crack and separation. I'll clean it up and take a new pic. Maybe that will reveal the issue more clearly.

Shtonecb500 · « **Reply #8 on:** May 09, 2021, 09:16:42 pm »

I tried having my lower case welded by a pro, he still told me there was no guarantee and it was in a very troublesome area, I didnt split my cases and he didnt attempt any welding from the inside.. It can be done, split your cases and have it done right. I would look for a new set of cases as well just in case.

Bummer.

DaveBarbier · « **Reply #9 on:** May 10, 2021, 02:01:59 am »

If that is on the left side of the bike at the back right above the pan that is not a crack. That is a documented casting flaw in all 550’s. Let me find a picture of mine.

DaveBarbier · « **Reply #10 on:** May 10, 2021, 02:11:15 am »

Here:

May not be a good picture but I assure you it’s not a crack. There have been other posts about this flaw on the forum if you search around. And anyone here that has a 550 can take a picture of theirs.

BrickWoll · « **Reply #11 on:** May 10, 2021, 07:16:41 am »

Quote from: DaveBarbier on May 10, 2021, 02:11:15 am

Here:

May not be a good picture but I assure you it’s not a crack. There have been other posts about this flaw on the forum if you search around. And anyone here that has a 550 can take a picture of theirs.

Thank you, Dave! That is exactly where it is. This is phenomenal news. I had begun to resign myself to missing the riding season after many hours of work. I'm curious if this is only on certain years or all 550s? I will search the forums for more info. Thanks again - made my day.

chiefum · « **Reply #12 on:** May 10, 2021, 07:28:53 am »

This is a crappy pic, but my 75 and 78 both have it in that location.

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DaveBarbier · « **Reply #13 on:** May 10, 2021, 07:30:40 am »

Quote from: BrickWoll on May 10, 2021, 07:16:41 am

Quote from: DaveBarbier on May 10, 2021, 02:11:15 am
Here:

May not be a good picture but I assure you it’s not a crack. There have been other posts about this flaw on the forum if you search around. And anyone here that has a 550 can take a picture of theirs.

Thank you, Dave! That is exactly where it is. This is phenomenal news. I had begun to resign myself to missing the riding season after many hours of work. I'm curious if this is only on certain years or all 550s? I will search the forums for more info. Thanks again - made my day.

I’m like, 99% sure it’s on all year 550’s but I could be wrong. Glad to help, I had that same sunken feeling when I saw mine. Actually surprised I was the first to reply with it.

minimo · « **Reply #14 on:** May 10, 2021, 07:32:21 am »

BrickWoll, let’s hope those are casting marks on your engine. I can’t wait to hear. Let us know :-)

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DaveBarbier · « **Reply #15 on:** May 10, 2021, 07:34:29 am »

Quote from: minimo on May 10, 2021, 07:32:21 am

BrickWoll, let’s hope those are casting marks on your engine. I can’t wait to hear. Let us know :-)

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It IS a casting flaw. No need to diagnose further.

minimo · « **Reply #16 on:** May 10, 2021, 07:37:22 am »

Quote from: DaveBarbier on May 10, 2021, 07:34:29 am

Quote from: minimo on May 10, 2021, 07:32:21 am
BrickWoll, let’s hope those are casting marks on your engine. I can’t wait to hear. Let us know :-)

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It IS a casting flaw. No need to diagnose further.

Such confidence! :-D
Well, that’s awesome news!

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Robbo · « **Reply #17 on:** May 10, 2021, 07:48:10 am »

My 75 CB550…

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DaveBarbier · « **Reply #18 on:** May 10, 2021, 11:27:16 am »

Quote from: minimo on May 10, 2021, 07:37:22 am

Quote from: DaveBarbier on May 10, 2021, 07:34:29 am
Quote from: minimo on May 10, 2021, 07:32:21 am
BrickWoll, let’s hope those are casting marks on your engine. I can’t wait to hear. Let us know :-)

Sent from my iPhone using Tapatalk
It IS a casting flaw. No need to diagnose further.
Such confidence! :-D
Well, that’s awesome news!

Sent from my iPhone using Tapatalk

Damn right! Haha

754 · « **Reply #19 on:** May 10, 2021, 12:01:00 pm »

Ok here is what happens.. I believe the dies are watercooled to aid chilling.
So dies close , hot molten metal get forced into dies, then when cooled enough dies open and part is ejected.
Sometimes a thousand times a day.. day after day.
Regardless of material.. and they choose wisely... due to the many cycles this leads to cracks like yours in the dies. BUT DOES NOT Affect function of part.. and dies are expensive so they run them that way for awhile..
So if thats the case, it will be a raised flaw.. not an inward crack or depression..

Don R · « **Reply #20 on:** May 10, 2021, 01:06:39 pm »

It sounds like Frank has run a die cast machine. I did for a couple weeks.
His theory sounds perfectly correct to me. After one 8 hour shift a QC guy re-melted all except three of my lawn boy crankcases. I apparently cooled the die too much. Or not enough.

DaveBarbier · « **Reply #21 on:** May 10, 2021, 03:09:08 pm »

I’m going with it was sabotage from an undercover Kawasaki executive.

754 · « **Reply #22 on:** May 10, 2021, 05:53:27 pm »

I have never seen a machine in person, but am a curious machinist type..
You want to see cracks, look at 750 cluch covers...

News:

Author Topic: Case Crack?? (Read 1576 times)