I'm converting a .25 FP to C/L and am installing a venturi and needle valve.
Simple question- Does the hole in the spray bar aim down or to the front or back?

Thanks,
John

John

The area right behind the spraybar is turbulent so the correct location for the hole is off to one side. It doesn't really matter which way you set the hole, forward or back in the airstream but here's how I do it.

Assume the centreline of the venturi is 12 o'colck/6 o'clock and set the hole at 4 o'clock.

I'm relying on memory for this but I think Ken is right that there is a tab cast on the side of the crankcase to help lock the spraybar. But the 4 o'clock or 8 o'clock position is the right one.

Cheers, Geoff

I've checked my FP 20s and FP 25s to find the following.

There are no locating tabs on either the old style or the new crankcases.

The hole in the OS spraybar, NVA Part No, 2231 1000, aligns with the centre of a flat on the hex at the spigot end. A dab of paint or a mark with a cut-off disk on the appropriate flat of the hex will give you a register that you can see and you should still set the hole at the approx 4 o'clock or 8 o'clock position. Either position should work but I face mine back toward the cylinder.

Cheers, Geoff