I changed to VM carbs on the XS650 some time ago and only had pod filters on them. Pod filters look ok but do nothing for eficient induction. so I buit two new pancake style air filters.
The base plate was turned up from a solid lump of 101.6mm aluminium then shrunk over the carb bell mouths with a .10mm tolerance. the outer plate i made from 1.7mm thick sheet aluminium, the lip beaten over on a former. The securing nuts are turned from 20 aluminium bar stock, shaped and knurled. The nuts were cut by eye, so aren't exact, but you'd need a calliper to pickup the difference.
The bell mouth has a nice stack shape, but the lead in is across the flat filter plate, so not perfect, but not far off. The only way to improve would be to sink the filter plate about 3 mm from the bell mouth and round the edges off, but the difference would be infinitesimal.
I also machined up a fuel distributor block. The block sits underneath the battery carrier front lip. It is drilled though from side to side, both sides culminating in an 8mm barb. Two brass barbs have been pressed into the front of the block and feed into the through hole, they are connected to the petcock via a couple of inline filters.
The through hole also equalises the fuel level on both sides of the tank when the level falls bellow the tank tunnel, thus ensuring one carb doesn't starve for fuel when the level gets low.
The base plate was turned up from a solid lump of 101.6mm aluminium then shrunk over the carb bell mouths with a .10mm tolerance. the outer plate i made from 1.7mm thick sheet aluminium, the lip beaten over on a former. The securing nuts are turned from 20 aluminium bar stock, shaped and knurled. The nuts were cut by eye, so aren't exact, but you'd need a calliper to pickup the difference.
The bell mouth has a nice stack shape, but the lead in is across the flat filter plate, so not perfect, but not far off. The only way to improve would be to sink the filter plate about 3 mm from the bell mouth and round the edges off, but the difference would be infinitesimal.
I also machined up a fuel distributor block. The block sits underneath the battery carrier front lip. It is drilled though from side to side, both sides culminating in an 8mm barb. Two brass barbs have been pressed into the front of the block and feed into the through hole, they are connected to the petcock via a couple of inline filters.
The through hole also equalises the fuel level on both sides of the tank when the level falls bellow the tank tunnel, thus ensuring one carb doesn't starve for fuel when the level gets low.
