I just noticed that the wheel of my DM double chain 8" giraffe has a broken spoke. Since both spockets are welded on, this makes replacing the spoke rather tricky. Anyone met this problem before? Any suggestions as to how to fix it?
Try bending (not kink) the spoke as necessary. You should be able to straighten it after you get it in. Use a thin sheet of plastic to protect the threads as you pull or push it along the cog.
I am striking out on Google, but there used to be spokes that had a kind of s hook instead of a head at the elbow. These spokes might make it easier to replace because you can just hook it into the hub. http://docs.google.com/Doc?docid=0AU1yHAVyWLMbZGhoN2M3ZGNfOWRnM24zcWZ6&hl=en
I wonder if you couldn’t just put a bend into a spoke like this and make your own. If it works then you’re set, and if not you will have a broken spoke which is what you have now.
Depending on how things are positioned, you may be able to drill a hole in the sprocket.
Or you could hack it up with a kevlar spoke:
http://www.peterwhitecycles.com/fiberfix.htm
Or just leave it that way, it’s probably not a big deal if it’s just one spoke.
It is not possible replace spokes, bending won’t work there is not enough space. You need remove the sprocket. Just run a grinder around the weld until you can snap it off. You can then replace the spoke. I have done this a few times, although I have ended up deciding to replace all the spokes. Dave only fitted rustless spokes, modern stainless ones are better. The same goes for the hub - it is of low quality. So I tend to replace this too.
Rebuilding you need to use the giraffe as a jig to match up the teeth on the sprockets. Fiddley but not hard, you just need quite a lot of patience and time.
I’ll second rogeratunicycledotcom’s opinion. It sucks, but he’s right.
Thanks Roger. I might wait until a few more spokes break until I replace the complete set as you suggest.
What sort of hub is suitable as a replacement? A BMX rear hub with threads for sprockets on both sides?
Why don’t you just stop riding it down the Unicon XV “real” Downhill course? 
In other words, giraffe spokes shouldn’t break much, unless you’re doing something beyond what the cycles are generally intended for. Not that there’s anything wrong with that. My old Schwinn has held up very well so far, even though I stripped off much of the axle threads with experimental pegs. Knock on wood…
Of course Roger’s advice is the proper approach to maintaining optimum quality in your giraffe. Tom’s suggestion is interesting; I hadn’t seen that before. Not very pretty but will keep the wheel strong. Welding the sprocket back on is the only hard part. It has to be absolutely centered to keep even tension. If you go that route, consider using a sprocket with a slightly different # of teeth than the top one. This will allow your tires to last many years even if you idle a lot.
No the hub is a standard kids rear hub. You dont use the threaded area at all, it is just using the common OD of the hub centre. This may take some finding.
Roger
I know what jtrops is thinking of. They used to be called “emergency spokes” - the idea was to be able to replace a broken drive-side spoke on a bike temporarily without having to remove the sprockets. I haven’t seen one for years though. Some of them had the z-bend on the hub end, then a length of flexible wire (like brake cable), then a threaded end for the nipple - that made them even easier to fit. Very similar to the fix tholub linked to.
Rob