Classics, Single Cylinder and 2 Strokes

Some single cylinder motorcycles have twin carbs. This includes pre fuel injected BMW F650, and some Aprilia Pegasos. Single cylinders with twin carbs have a vacuum point to balance the carbs. An example of a bung is shown left, and balance pipe shown below left on a 4 carb model. Twin carbs can have the same.

If this is the case, either tee into the pipe, or replace the bung with a damper elbow, see our general vacuum connections page.

Remove the rubber inlet manifold. Drill a 4mm hole in the inlet manifold, being careful to remove any swarf created.

Fit the M5 spigot from the Scottoiler kit, using a silicon type sealer to ensure an airtight seal, and washers supplied in the kit, as shown left.

Re-install the rubber inlet manifold.

On some bikes however, there is not enough clearance to fit the spigot onto the rubber manifold. If this is so, it is necessary to drill and tap a hole on the inlet tract of the carb.

Drill small hole in inlet tract of the carb. Tap small hole with an M5 tap, to fit the M5 spigot. Note, you may find that the aluminium of the carb soft enough allow you to tap the hole using the spigot, rather than a tap.

This hole must be forwards of the throttle butterfly. Once the holes have been tapped, make sure that there is no swarf  in the carb inlet.

Fit the M5 spigot as supplied in the basic kit, using a silicon type sealer and washers to ensure an airtight fit.