So, while I'm waiting for more engine parts to arrive for the winter-time engine upgrade to my 2004 950 Adv, I read some horror stories about early-model swingarms cracking and breaking. There seems to be no end to the number of parts that were updated on these 2003-2004 bikes! Some of the very helpful inmates here clued me in on which other 950/990 models swingarms would also fit the adv, but they are all quite spendy. So, I decided to add some bracing to my swingarm, after I examined it closely, and found no evidence of cracks.
The early arms have a large empty spot to the right of the lower shock mount. Even with my somewhat dulled hindsight, this looks like a bad idea-
Sorry, not a great pic, and I don't have a pic of the updated arm, but they have the same width cross-bracing on both sides of the lower shock mount.
So, I fabbed some bits to complete the missing portion of the bracing-
After welding the first piece in place, I fitted the upper piece, which has had the upper edge trimmed to match the contour of the top of the swingarm-
With that welded in place, I added a small piece going forward from the shock mount-
With all these parts in place, we have a nice little boxed area that more or less mimics the structure of the updated arm-
Now I just need to put a top on the box. But first I drilled a drain hole at the lower right corner of the new box, which ensures any water that sneaks by the lower shock bolt can drain into the swingarm leg-also drilled.
It also vents the box-so you don't have molten aluminum spraying around when you weld it closed!
Now there is adequate bracing for both swingarm legs, with a more even load path, just like a "normal" swingarm-
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