Author Topic: Cracked Case (see pic) - recommendations.. (Read 6452 times)

mrhoades · « **on:** April 20, 2009, 10:29:58 AM »

Well I got the cases apart on my 74 CB750 rebuild only to find that the upper case is cracked , right behind the drive sprocket... probably from a chain failure or somethin gettin kicked up/wedged real good in that little nook of the case. Appears the PO used a bit of JB Weld as a fix .... but I would like to investigate a more permanent & reliable fix... Last nite I dreamt I was on a nice 100 mile ride, when all of sudden the fix failed...spewing hot oil up my wifes leg.

http://i681.photobucket.com/albums/vv176/rhoades999/cc1.jpg
http://i681.photobucket.com/albums/vv176/rhoades999/cc2.jpg
http://i681.photobucket.com/albums/vv176/rhoades999/cc3.jpg
http://i681.photobucket.com/albums/vv176/rhoades999/cc1.jpg

You can see from the pics the crack is almost rectangle in shape..where one side and bottom is a hairline fracture and the side opposite is where JB was used...since this side was pushed in a bit and the crack gap is about 3 MM's wide.

Anyone have experince welding a fix like this

Anyone know a good welder who has experience with welding 35 yr old M/C cases ??
Any input on some of the brazing fixes I have come across like Lumiweld or DuraFix???

Any and all input much appreciated... THANKS .. MIKE

kghost · « **Reply #1 on:** April 20, 2009, 10:48:48 AM »

Think I'd TIG weld that crack up.

Chamfer down into the crack...grinding a V then weld it back up.

MRieck · « **Reply #2 on:** April 20, 2009, 11:42:33 AM »

Quote from: kghost on April 20, 2009, 10:48:48 AM

Think I'd TIG weld that crack up.

Chamfer down into the crack...grinding a V then weld it back up.

I agree

cleveland · « **Reply #3 on:** April 20, 2009, 11:48:31 AM »

You could likely pick up a replacement case pretty cheap.

hopefuldave · « **Reply #4 on:** May 05, 2009, 07:33:30 AM »

Trouble with a replacement case is that they're line-bored in pairs for the bearings, could find the crank nipping up or worse...

A (matched) pair of cases would work, but that means a new engine number (as does a new upper case), some places that means changing paperwork and some owners clubs count that as a black mark against "originality"

TIG welder time!

Dave H.
(The engineer formerly known as Homeless)

"Rules are for the obedience of fools, and the guidance of wise men" - Douglas Bader

nokrome · « **Reply #5 on:** May 05, 2009, 01:00:47 PM »

looks like a nice clean crack....very weldable

nice clean crack

Scrubs · « **Reply #6 on:** May 05, 2009, 01:18:33 PM »

the low temp solder rods are good but work best on flat surfaces and that case is pretty thick for the money it would cost you
to invest in the rods I would get a tig welder just to run a bead down it. Peace of mind.

RRRToolSolutions · « **Reply #7 on:** May 05, 2009, 01:40:05 PM »

Now here is what might have been a crack, but then completely broken away.

Without question, a good welder can turn that case to like new. Here is a 1974 GT750 case that suffeed a chain break some time in it's previous life...

mystic_1 · « **Reply #8 on:** May 05, 2009, 02:15:19 PM »

So, anyone have a good resource for TIG weldors in the Chicago area who are able AND willing to do this kind of work? I have a couple of sets of cases that might be salvagable in the right hands, but don't want o pay a fortune for someone why may turn out to be a hack.

mystic_1

B.O.X.N.I.F.E. · « **Reply #9 on:** May 05, 2009, 02:19:41 PM »

You could always put an ad up on craigslist, lots of guys who could do this work cheaper on the side from home.

mystic_1 · « **Reply #10 on:** May 05, 2009, 02:20:55 PM »

True, but I'd prefer to find a weldor who has worked on small air-cooled engine blocks before, rather than someone who's certified to build bridges, if you know what I mean

Plus a recommendation from a site member carries quite a bit of weight I think.

mystic_1

B.O.X.N.I.F.E. · « **Reply #11 on:** May 05, 2009, 03:31:18 PM »

You could always check with the VW guys

Kevin D · « **Reply #12 on:** May 05, 2009, 04:39:40 PM »

Don't forget to get a new drive sprocket:

http://i681.photobucket.com/albums/vv176/rhoades999/cc2.jpg

XN · « **Reply #13 on:** May 05, 2009, 11:04:57 PM »

Go to your local airport and ask a mechanic where to find a certified welder. Company's that are certified to do aircraft welding know their stuff. You may pay a little extra, but you know it will be done right

johnny_from_bel · « **Reply #14 on:** May 06, 2009, 01:20:13 AM »

Quote from: mrhoades on April 20, 2009, 10:29:58 AM

Any input on some of the brazing fixes I have come across like Lumiweld or DuraFix???

Any and all input much appreciated... THANKS .. MIKE

I use lumiweld. Its easy and strong if you take your time and do it properly.

jtb · « **Reply #15 on:** May 06, 2009, 05:57:58 AM »

Quote from: mystic_1 on May 05, 2009, 02:15:19 PM

So, anyone have a good resource for TIG weldors in the Chicago area who are able AND willing to do this kind of work? I have a couple of sets of cases that might be salvagable in the right hands, but don't want o pay a fortune for someone why may turn out to be a hack.

mystic_1

If you don't mind shipping them to GA, Big Jay on this forum can handle it. He welded a tab back on a carb for me, reasonable, and good work.

MCRider · « **Reply #16 on:** May 06, 2009, 06:12:45 AM »

Quote from: jtb on May 06, 2009, 05:57:58 AM

Quote from: mystic_1 on May 05, 2009, 02:15:19 PM
So, anyone have a good resource for TIG weldors in the Chicago area who are able AND willing to do this kind of work? I have a couple of sets of cases that might be salvagable in the right hands, but don't want o pay a fortune for someone why may turn out to be a hack.

mystic_1
If you don't mind shipping them to GA, Big Jay on this forum can handle it. He welded a tab back on a carb for me, reasonable, and good work.

Did you mean CA rather than GA?

MCRider · « **Reply #17 on:** May 06, 2009, 06:20:15 AM »

To OP MRHOADES and any interested party:
I have a set of cases that have been stripped, blasted with plastic media and the studs are removed. (More work than expected, one broke and I'll have to remove the stub yet.) I'm hoping for $100. High I know, but they are ready for paint and HD studs. I have to finance my budget overruns by selling excess parts.

To MYSTIC et al: Also, I have one set that has a crack in the motor mount. It was in an accident. I'll be taking it to Saldana Racing Products in Brownsburg IN to be welded up and line drilled. The machinist spends his days TIG welding aluminum radiators and oil tanks for sprint cars, stock cars etc. He is very good. I'll explain the problems of cracked cases from chain failure to confirm he is comfortable doing that work, and report back, if anyone can use them.

Sometimes shipping from Chi to Indy (B Burg) not much more than time and effort to drive across town.

mystic_1 · « **Reply #18 on:** May 06, 2009, 09:32:37 AM »

Excellent Ron, sure appreciate that. I have one motor with chain damage, another with a pinhole leak in the oil feed from the main gallery to the right-most crankshaft bearing, it leaks into the points cover area. Probably have several other parts that could be salvaged if I knew a good weldor, I just hate to throw any of these things sway, ya know?

Do let us know what you find out.

mystic_1

mystic_1 · « **Reply #19 on:** May 06, 2009, 10:50:45 AM »

Quote from: jtb on May 06, 2009, 05:57:58 AM

If you don't mind shipping them to GA, Big Jay on this forum can handle it. He welded a tab back on a carb for me, reasonable, and good work.

Thanks for the referral, will definitely keep it on file, but I figure that for something like a crankcase, shipping charges both ways would probably be prohibitive.

mystic_1

jtb · « **Reply #20 on:** May 06, 2009, 04:29:20 PM »

Quote from: jtb on May 06, 2009, 05:57:58 AM

Quote from: mystic_1 on May 05, 2009, 02:15:19 PM
So, anyone have a good resource for TIG weldors in the Chicago area who are able AND willing to do this kind of work? I have a couple of sets of cases that might be salvagable in the right hands, but don't want o pay a fortune for someone why may turn out to be a hack.

mystic_1
If you don't mind shipping them to GA, Big Jay on this forum can handle it. He welded a tab back on a carb for me, reasonable, and good work.

Sorry, Big Jim.

mystic_1 · « **Reply #21 on:** May 06, 2009, 04:43:46 PM »

Heh, so Big Jim in CA, not Big Jay in GA.

Got it!

I think

mystic_1

Jim F · « **Reply #22 on:** May 06, 2009, 05:00:40 PM »

No there talking about me

I am BIG-JIM in Georgia

If you would like to send your case to me I will see what I can do

Here is my web site

Ive done some work for some of the guys on the forum and its all turned out nice

www.jmfmicroweld.com

RRRToolSolutions · « **Reply #23 on:** May 06, 2009, 06:56:58 PM »

Yes, I will give Jim a big thumbs-up. He did me proud on a special bracket for a remote idle adjuster. Awesome beads, the man knows his stuff.

Best Regards,
Gordon

jtb · « **Reply #24 on:** May 07, 2009, 05:49:14 AM »

Quote from: Ilbikes on May 06, 2009, 06:56:58 PM

Yes, I will give Jim a big thumbs-up. He did me proud on a special bracket for a remote idle adjuster. Awesome beads, the man knows his stuff.

Best Regards,
Gordon

+ 1

MCRider · « **Reply #25 on:** May 07, 2009, 08:21:08 AM »

Quote from: mystic_1 on May 06, 2009, 09:32:37 AM

Excellent Ron, sure appreciate that. I have one motor with chain damage, another with a pinhole leak in the oil feed from the main gallery to the right-most crankshaft bearing, it leaks into the points cover area. Probably have several other parts that could be salvaged if I knew a good weldor, I just hate to throw any of these things sway, ya know?

Do let us know what you find out.

mystic_1

Being that you're a little closer to Indy than GA, this may be of interest. I went to the shop I'm using for welding and mods "Saldana Racing Products" today. http://www.arsatweb.com/saldanaracingproducts/index.shtml
They are rebuilding their website and there is nothing in the services link. The catalog gives the best idea of what they are up to. Besides the production pieces in inventory, which they make, they are interested in the one-off repair and alteration/fabrication business. They repair lots of broken sprint car pieces, he said they have some Porsches in right now, stock cars etc.

I gave them 3 sets of crankcases. My current project to have the motormounts linebored to fit the OS SS motor mount bolts they made. The next project to have the motor mount repaired, it was cracked in an accident, and bored to fit as in #1. And the 3rd set is for sale but they had a broken off stud. I've removed broken studs before but its a #$%*. THey said they would weld a rod to the stud and heat the case and back it out.

Dang, I just got a call from Saldana and everything is done! Gotta go in a minute. I could have waited, had some breakfast, and picked it up.

So about fixing broken cases from chain damage. THey said no problem as I figured. But it would be a case by case (no pun) decision. If all the pieces are there, better. If just cracked, best. THey grind the crack in a vee as has been mentioned here, then TIG it up.

But, if the pieces are loose or missing, harder. Their concern is getting the 2 case halves surfaces to match. They have tools to do it, but at some point, it may not be salvagable.

So gotta go. I'll have pictures of the motor mount crack before and after.

mystic_1 · « **Reply #26 on:** May 07, 2009, 09:11:04 AM »

Heh, OK so the worst case I have at the moment is my original K0 case, it had already been cracked and re-welded at some point in it's lifetime before I got it. When I had my chain incident (suspect debris pulled through by the chain) this are re-cracked. All of the pieces are there but there's an extensive network of cracks, not just one big crack. There are multiple pieces, and I cna tell that they're only staying in place right now because they're jammed against each other.

Up until now I've been considering this case a complete write-off, but just for giggles Ron if you get a chance ask your guys what they think of a case that's been broken, welded, and then broken again, then band-aided with JB-weld

mystic_1

mystic_1 · « **Reply #27 on:** May 07, 2009, 09:14:47 AM »

Quote from: big-jim on May 06, 2009, 05:00:40 PM

No there talking about me

I am BIG-JIM in Georgia

If you would like to send your case to me I will see what I can do

Here is my web site

Ive done some work for some of the guys on the forum and its all turned out nice

www.jmfmicroweld.com

Hi, Jim

Thanks for the offer, when I think of it your process may be ideal for one of the cases I have, the one with the pinhole leak in the oil passage. The leak is deep in the points cover area so I figure welding in that area may be tricky but looking at your website I can see that your process is capable of things a larger welder couldn't do. I think I'd made the mistake of assuming that your process could only be applied to small parts, but I see that on some jobs you have built up quite a thickness in multiple layers of multiple passes. Cool!

Let me put some info together and PM you, then you can give me your opinion on the project.

mystic_1

mystic_1 · « **Reply #28 on:** May 07, 2009, 09:24:19 AM »

Quote from: mrhoades on April 20, 2009, 10:29:58 AM

Anyone have experince welding a fix like this Anyone know a good welder who has experience with welding 35 yr old M/C cases ??
Any input on some of the brazing fixes I have come across like Lumiweld or DuraFix???

Any and all input much appreciated... THANKS .. MIKE

mrhoades,

Hope you don't feel I'm hijacking your thread! One of my cases is cracked very similarly to yours, only the chuck was pushed in enough that the inner surface came into contact with the transmission gears and got ground away! Guess I found the source of the bright silver glitter in my oil lol!

So you mentioned the aluminum brazing rods, I did a post in the Tips and Tricks section where I explored this stuff. I had problems getting a large piece like a crankcase up to sufficient temperature for this stuff to work. Smaller pieces are fine but a big hunk of aluminum is just too good of a heat-sync, so you can't get your working are up to temperature. Aside from that it's pretty easy stuff to work with. If you get some to experiment with, don't use MAP gas, too much soot produced with that stuff so it contaminates your work.

Hope some of the other information in this thread is good for you too.

I'm actually going to also follow up on XN's idea of checking out the local airport. I'm fairly close to several airports in the area, one just a couple of miles from the house, and it's a pretty good bet that someone will either be a weldor or know a weldor.

cheers
mystic_1

johnny_from_bel · « **Reply #29 on:** May 07, 2009, 10:34:25 AM »

Quote from: mystic_1 on May 07, 2009, 09:24:19 AM

I had problems getting a large piece like a crankcase up to sufficient temperature for this stuff to work. Smaller pieces are fine but a big hunk of aluminum is just too good of a heat-sync, so you can't get your working are up to temperature.

I just put the piece in the oven at max temp for a few hours.

mystic_1 · « **Reply #30 on:** May 07, 2009, 10:59:52 AM »

Yes that works, gotta work quickly once you pull it out of the oven though. The alumiweld flowed out properly then but it was still a pain in the butt. In the end I decided that I didn't like the idea of relying on it for this particular application, main bearing oil supply is nothing to mess around with if you want your motor to not eat itself

Also had some problems with porosity, high pressure air would still find it's way past the alumiweld, but slowly (very small bubbles. This stuff changes state rapidly from liquid back to solid, my theory is that the rapid contraction leaves stress lines or 'cracks' in the material.

For other applications, though, I think it's great stuff.

mystic_1

MCRider · « **Reply #31 on:** May 07, 2009, 11:16:01 AM »

mrhoades: Your crack is most like the crack i had in my motor mount. I'll post some pictures tonight. You didn't mention (that I saw) where you are, so don't know if this is any help to you. I would recommend Saldana in Brownsburg IN. Just got my cracked case back fixed nice and purdy for $30. Had I waited they would have done it while I waited. Its about a 20 min drive for me.

Everybody is different on this score, but for that kind of money, I can't bring myself to try do it yourself remedies, many of which I'm sure yield a fine result. That's just me. I would bet money that a skilled welder lies within your reach.

Mystic: I would say Saldana can and would do anything that's possible to do to our aluminum engine parts. But yours is so messed up, I'm sure they would say they would have to see it first.

While picking up my parts i was nosing around the shop. Bob the welder had just finished a custom aluminum radiator with integrated tranny cooler for a drag racer from AZ and it was beautiful. $400 made to specs. Custom set fittings, etc. Pictures tonight.

So I asked about my next project, I want a custom oil tank for a CB750 to mount between the frame rails above the swingarm pivots serving as the gusseting for the swingarm pivot with an integrated heat sink/radiator. he said sure no problem. Can't wait.

The idea of going to the airport has merit as well. I think the people we need to do this work are usually closer than expected. Unless you're down some fire road in Montana.

MCRider · « **Reply #32 on:** May 07, 2009, 11:22:46 AM »

mrhoades: I just had to comment on that countershaft sprocket in the second picture. I see a chipped tooth! The other tooth appears to have the "sawtooth" wear characterisitcs. Yikes!

MCRider · « **Reply #33 on:** May 08, 2009, 09:42:00 AM »

Here's the crack before:

and after, they ground a groove into the crack, then clamped it to draw it together.

Then reamed the hole back out. There was actually a second crack at about 8:00 oclock that i don't have a before picture on. But you can see the repair here

Sorry the flash kinda washes out the detail.

cleveland · « **Reply #34 on:** May 11, 2009, 02:44:34 PM »

Nice to see it looking better. What did it end up costing?

MCRider · « **Reply #35 on:** May 11, 2009, 02:51:40 PM »

Quote from: cleveland on May 11, 2009, 02:44:34 PM

Nice to see it looking better. What did it end up costing?

I had several small jobs for them totalling 2 hours at $60 per. The 2 cracks together were probably $30.

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Author Topic: Cracked Case (see pic) - recommendations.. (Read 6452 times)

hopefuldave