I bought a couple of VM34 carbs to replace the BS38s. Unfortunately the BS carb diaphragms started developing lot of little holes, far to many to patch. I priced diaphragms in Oz, $140 each, damned if I was going to pay that. JBM in the US have diaphragms for $19, but they're not posting to Oz, so that settled it.
The VMs arrived and came with a cable and two manifolds. I fitted them only to find the cable interferes with the petrol tap, the common fix for this is to angle the charts over, not this little black duck! Anyway I contacted the seller who stated it was a very rare problem, 3 in 500. Googling revealed a different story, it's quite common due to not all XS650s not being the same.
So, I decided to turn up a couple of longer manifolds to site the carbs behind the fuel taps. I first spun up a 40mm spigot with a lip, next I turned up a 25mm plate and pressed the spigot in place. It turned out excellent so I made another exactly the same.
The manifolds site the carbs 10mm behind the tap, but the tap outlet spigot was right in the middle of the carb cable. Easily fixed, I swapped the taps, right to left and left to right which placed the spigot at the front of the tap, thus missing the cable altogether.
Quite a neat fix which looks pretty good. Armchair experts like to harp on about longer manifolds changing the torque and power outputs, but really it makes no difference. Only a dyno could pick up any difference and that would hardly register any difference at all.