Reply To: Drain Tube
David Faulkner
It’s just a fine tube part 453 112 which you can buy for 3 euro complete with gland nut from Fransens in Belgium (available elsewhere though costs a lot more) so at that price it’s not worth making one….
The end is simply crushed to restrict the amount of air that can be drawn in, too large a hole and it affect the mixture
CTA have an ‘engine tips’ guide which explains:
Traction Tip 28: Fuel overflow pipe.( drain pipe)
This pipe is bolted on the side of the intake manifold and bent so its leading downwards between the engine and the side of the “jambonneau”. Trough this pipe the redundant fuel in the manifold has to be carried away. For this there is a little hole at the end of the pipe. Take care that this hole is not blocked or even more important it’s not too big. If the hole is to big the engine will take in a lot of false air, this influences the stationary adjustment (idle) of the engine. It can not be adjusted properly anymore. Using pliers you can crimp this hole to a size of about 0,5mm. If you, when the engine is running, keep your finger against the hole you can feel the vacuum created by the engine. If you changed the size of the hole, you have to adjust the stationary idle of the engine.