I have posted a picture of this before, but while I was working on my motor today I thought that I would take another picture of my cracked case so I can get some advice from some of the tig welders here. I think that I might be able to machine the boss off, grind the crack out, have it tig'ed then maybe add a larger fillet piece of aluminum to the area to strenghten the area and re-drill tho shock mount hole. I have another set of cases that I'm building an 88 with. I just think that this case may be repairable.

Note this is the lower front engine/shock mount bolt hole (cam side).http://xlforum.net/photopost/data/500/Cracked_Engine_Case11.JPG

You should have no problem getting it welded, but you should find out why it cracked in the first place. If you want a more solid fix you could take off the broken part and fill the area with weld and it will be better than just welding the crack in the casting. Find a shop that does TIG and ask their opinion.

That cracks in that location from wheelies :D It could also just be a poor design by Buell. Why build a bike that loves to wheelie if it can't handle the stress?

The Buell shock mounts with a bracket there, I think (hard to orient the picture in my brain) and when you come down on the front wheel, it stresses the shock and that stresses the case right there. The last one I saw was completely cracked in the front, and it was definitely from wheelies, according to the owner. Like he came down, and the front shock mount broke the case.

That is a pic of the cam side, with the photo rotated 90 degrees CW, right?

--Chris

Actually I would almost bet that the bike has been crashed as my X1 had a break in the exact same place after it lowsided into a car that turned right in front of me:eek:

Interesting. I wonder if L.B. is still watching this thread? It's kinda old.

--Chris

Thanks for the reply's! The previous owner, who I happen to work with, raced it at dirt drags at the bike rallys. He had another fellow ride it for him though, who actually won a few events. The story I got was that it got away from them at "Little Sturgis". I bought knowing that it had a oil leak and was told the whole story, but I still hoped for the best...

I believe that the case can be repaired, but I'm not a welder although I have played around with a TIG a while back. The crack isn't noticeable from the back side of the case. I wonder if the cracks are ground out and the boss is then machined flat then re-welded with a fillet piece of aluminum the thickness of the boss that was removed it would be stronger than before and not leak. The crack goes down into the bolt hole which would make it difficult to if the cracks aren't machined out first I think...

The Buell only has 3300 miles and only a small fraction of that was done by my co-worker. I just thought that I will try get the case repaired since I will have a big part of an extra motor when I done...

That cracks in that location from wheelies :D It could also just be a poor design by Buell. Why build a bike that loves to wheelie if it can't handle the stress?

The Buell shock mounts with a bracket there, I think (hard to orient the picture in my brain) and when you come down on the front wheel, it stresses the shock and that stresses the case right there. The last one I saw was completely cracked in the front, and it was definitely from wheelies, according to the owner. Like he came down, and the front shock mount broke the case.

That is a pic of the cam side, with the photo rotated 90 degrees CW, right?

--Chris

Chris, I agree that it seems to be a poor design... It's asking a lot of the Sportster engine to suspend it the way they did in the tube frame Buells.

The picture is of the cam side rotated 90deg. as you said...

I can't see that the bike was crashed all that hard since nothing is really messed up aside from the tail light, license bracket, and tweeked handlebars and levers. The fuel tank wasn't even scratched... The shock pulls back against the engine normally. I guess it just wasn't ment to be bounced across dirt fields...

I guess it just wasn't ment to be bounced across dirt fields...
Nope, that's what Sportsters are for!

--Chris

Caught this a bit late but here goes...I have seen this failure on a couple of tubers. It is the result of the shock mount bolts having insufficient torque. The loss of clamping force allows the bolts to load in SHEAR instead of tension. Look at the fracture in the pic. It is evident that the material is displaced and broken away towards the front of the bike.

A wheely does not impose any serious loads on the chassis. A botched (slam down) landing can. When the bike comes down, the heavy engine wants to rotate about the rear axis and continue downward. The top mount is heavily stressed and will shear the head bosses in extreme repeated cases.

There is a very small arc motion at the shock mount,downward and back as the rubber donut in the top mount deflects down. This motion puts a small force into the shock, and to a lesser degree the swingarm. The same loads on the front shock mount can be generated by topping the shock (fully collapsed) as in too much preload/ insufficient rebound damping.

Obviously the shock mount is loaded in tension and pulled rearward the majority of the time. BUT: if the bracket is not FIRMLY clamped to the cases this type of failure will occur. It appears that the bolt hole in the pic was elongated before it broke. That is consistent with looseness and bracket movement/ shear load on the bolts and engine case.

The point is that wheelies including a hard landing now and then DO NOT overload this part of the chassis unless things are a bit loose. The slammers are really hard on the top mount. Not to mention the front end...

A good welder can fix it. Make sure the boss is re-spotfaced or counter bored so that the bracket mates squarely and clamps properly when bolted.

Caught this a bit late but here goes...I have seen this failure on a couple of tubers. It is the result of the shock mount bolts having insufficient torque. The loss of clamping force allows the bolts to load in SHEAR instead of tension. Look at the fracture in the pic. It is evident that the material is displaced and broken away towards the front of the bike.

A wheely does not impose any serious loads on the chassis. A botched (slam down) landing can. When the bike comes down, the heavy engine wants to rotate about the rear axis and continue downward. The top mount is heavily stressed and will shear the head bosses in extreme repeated cases.

There is a very small arc motion at the shock mount,downward and back as the rubber donut in the top mount deflects down. This motion puts a small force into the shock, and to a lesser degree the swingarm. The same loads on the front shock mount can be generated by topping the shock (fully collapsed) as in too much preload/ insufficient rebound damping.

Obviously the shock mount is loaded in tension and pulled rearward the majority of the time. BUT: if the bracket is not FIRMLY clamped to the cases this type of failure will occur. It appears that the bolt hole in the pic was elongated before it broke. That is consistent with looseness and bracket movement/ shear load on the bolts and engine case.

The point is that wheelies including a hard landing now and then DO NOT overload this part of the chassis unless things are a bit loose. The slammers are really hard on the top mount. Not to mention the front end...

A good welder can fix it. Make sure the boss is re-spotfaced or counter bored so that the bracket mates squarely and clamps properly when bolted.

Thanks, for you your well written reply! It's not too late either, since I haven't done anything with these cases yet..

The difficuly part, as I see it, in the repair would be repairing the crack enough to prevent it from leaking again.. I might be able to plunge or counterbore the hole enough to remove the crack, then install and weld a new aluminum plug, remachine the boss and hole..

I'm in the process of biulding an 88" engine with stage 3 heads. When I'm done, I should have most of my original parts left over to rebuild it, minus tranny.. A good excuse for a 6 speed here.. As if I need one..:frownthre

Your welcome. If you can get it on a mill it would be nice to plunge mill out the whole area and weld in a piece of round stock. Then re-drill the hole and spot face the mounting pad to proper depth and perpendicularity. That would be a real strong repair. The case should be heated to about 400F before welding to reduce stress. If your welder does not know this find another welder.