FAQ  r1.6

Breather

1. Why do I need a breather?

· Air in the container expands and contracts with temperature changes - which can be significant if the container is mounted in the typical underseat area.

· If the air in the container can't expand and contract freely then this may cause sealing problems in the container's cap and leads. The same point applies to trapping/kinking the breather.

· If the pump is forced to suck too hard, it may cause seals in the lines to pop, allowing the pump to draw air, instead of oil from the container - and will of course make the oil delivery unprdictable.

2. Is the breather tube routing important?

Yes, critical!

The breather tube's outlet should be well above the highest point of the breather intake in the container.

If the tube fills with oil, and the outlet is below the intake, there will be a syphon action which can cause oil to drain out. This is potentially dangerous and can cause an accident if it gets on the back tyre

· Re-position the container so that the breather intake does not come under the oil level

· Do not overfill the container (as a rule of thumb, the oil level should be at least 10mm below the breather inlet)

· Do not locate the container with the cap facing the left of the bike. When the bike is on its side-stand, the breather could become submerged and allow the oil to drain out.

· Check the breather tube is not trapped or kinked

3. What is the best breather tube routing? Any other tips?

· The breather is best routed along the length axis of the bike, with its outlet at least 5cm above the highest point you can foresee the for breather intake (eg. when the bike is on its side-stand)

· The greater the height difference between the intake and outlet, the better

· The longer the breather tube, in general the better (30cm is a good length, but there's no harm in a longer tube if you have the space - you can even coil it up)

4. What should I do if I see the breather tube is filled with oil?

· Try and work out why the breather intake came to be submerged in the first place

· Don't forget that the higher the oil level, the more often the breather intake will be submerged temporarily under braking, acceleration and cornering forces. This is no problem as long as the breather intake is normally exposed, that's to say, located in the air in the top of the container.

· Bear in mind, if the tube has oil in it, and the air in the container heats up and expands, then this oil can be blown out because it forms a plug.

· If you clear the oil (see below), and then soon after see that the line is again filled, then

· Consider running with a lower oil level in the container

· and/or ensure you use a long breather line with a high outlet (the shorter the line the more likely that oil can start a syphon action)

· To clear an oil-filled breather line:

· Ensure the breather intake is not currently submerged

· Unplug the breather line from the brass tubing and drain it (blow into it if necessary)

· Reconnect the line