1974 XS/TX650 rebuild

[th62]

I bought some round slide VMs in kit form, they come with extra jets, cables , manifolds and rubber boots for mounting. The kit is put together as a kit expressly for the XS650. However, when I mounted them on the bike I found I had to tilt the carbs over quite a bit for the carb cables to clear the petcocks, amateur hour in my opinion. To stop the carbs hanging up on the petcocks, I turned up an aluminium manifold, 40mm longer than the kit manifolds . It moves the carb back behind the tap, so I can sit the carbs upright and get to the adjusters. Problem with is, the fuel spigot on the tap now gets in the way, so I swapped the taps left to right, right to left, so the spigot now faces forward. Rather than turn the manifold up from one 90mm round, solid lump, I turned the spigot up from a 50 mm piece, leaving a 2.5mm lip at the bottom. I used one of the spacers I turned up beforehand for the flange, enlarged the hole and forced the spigot through. The lip actually seals against the cylinder head stopping the spigot from shaking itself loose. Longer inlet tracts do move the torque curve further down the rev range, but like a lot of performance mods, twin carb conversions, porting, velocity stacks, and so, the difference in performance, particularly on a street bike, would be hard to pick up, only a dyno would pick up the difference. This was only a rough manifold to try it out, I'm happy with this solution, so I'll turn up two identical manifolds over the next few days. Once done, I'll polish the float chambers and screw tops and paint the bodies black to match the engine.