A lesson in over thinking. Fuel filter /distributor.

Due to the tunnel in the TX650 fuel tank the fuel level can vary from side to side, so when the fuel level gets low enough one side can run dry. The original BS carbs had a fuel link between the carbs so regardless of how low the fuel level in the tank got both carbs still got fuel.

As the VM carbs I replaced the BS carbs with don’t have that link I machined up a fuel distributor block to ensure both sides of the tank retained the same fuel level.

A small block of 6061 was mounted on the lathe and an 8mm spigot was machined each end, these spigots attach to the carb inlets. A 5mm hole was then bored through linking both spigots. Two 6mm holes were drilled through the front of the distributor to intersect the 5mm through hole and two 6mm brass spigots were then turned up and pressed into place, thus linking all four spigots.

Two 6mm holes were tapped at the top of the distributor to serve as mounting points.

Flexible fuel lines interrupted by inline filters link the taps to the inlet barbs at the front of the unit and the 8mm barbs at each end of the distributor are linked to the carbs via flexible fuel line. In effect the distributor keeps the fuel levels on either side of the tank the same, so both carbs are served fuel regardless of fuel level in the tank.

I love to overthink things, surely an integral filter in the distributor would be better than two unsightly, plastic inline filters. Back onto the machinery to machine this next monstrosity:

A largish lump of 6061 was chucked on the lathe and turned down to 40mm, a 20 mm hole then bored through to within 10mm of the bottom, the lower section of the 20mm hole enlarged to 32mm, leaving a small 20mm lip, and a 20mm sintered bronze filter was inserted in the hole at the top.

A 6mm hole was bored through the base intersecting the 28mm hole, two 6mm brass barbs were then turned up and pressed into either side at the bottom of the unit. I then turned up a top cap to fit, recessing the base section to take a rubber O ring. A 6mm blind hole was drilled through the side of the cap and a 10mm hole drilled from the bottom to intersect the 6mm hole, then two 6mm holes drilled through the top to intersect the 6mm hole in the side and two brass barbs pressed into place on top of the cap.

The distributor top and bottom were then clamped together and two holes drilled through the top cap and on down to the base for about 15mm, then tapped with an M4 thread.

A third spigot was drilled through the base intersecting the 28 mm bore, this spigot is connected to a tap underneath the bike and used to purge the fuel from the distributor thus negating the need to dismantle the distributor to clean the sintered bronze filter.

A mounting bracket was then formed from 3mm stock, mounted to the bottom of the unit via two rubber grommets and then mounted to the cam chain tensioner, siting the unit between the two carbs.
The unit looked good on the bench, but despite working well, when mounted on the bike, connected to both taps and carbs it was just plain UGLY.

So, another item for the useless parts bin. Eventually the first distributor also found its way to the useless parts bin and now one carb can be run dry, but only for a klm or two before the tank runs dry.

A lesson in overthinking! But it was interesting to make, ensuring it didn't leak, lining up fuel galleries and ensuring mounting screws didn't intersect any of the galleries.

 

The gift of creativity is priceless.

 

Any job worth doing is worth overthinking! Pretty cool machine work if nothing else. An old DT250 I had with a big tunnel in the tank...it was the first with the Monoshock(!)...anyhow, it had one petcock and then a separate nipple on both sides of the tank that got connected by a chunk of fuel line routed under the monoshock after the tank was installed. A little inconvenient for tank removal, but super simple. I've considered doing the same on my 1100 to eliminate the octopus.