Ignition Advance Vacuum Line

[Spyglass]

I replaced this old vacuum line and noticed an arrow on the nozzle 41R-14489-00-00.

Is this pointing the right way?

I assume this is looking for vacuum to signal the 22N-82380-10-00 pressure sensor and since it's a naturally aspirated engine there won't ever be positive pressure.

It doesn't seem to restrict airflow in either direction. Slightly bigger diameter on the right side as it's facing in the picture.

Thanks.

 

[Fire-medic]

Look up information in the factory service manual, it is on here in multiple places. That will tell you what direction the arrow was supposed to point.

I suspect the arrow means that if it is supposed to be pointing towards the sender unit. However checking the service manual will give you the 'no guessing' info you need

 

[Spyglass]

Yes, that's the first place I looked.

I have found a few things that were suspect on the bike, so I'm assuming nothing is as it should be until verified elsewhere.

The manual does mention a "pressure signal" from the joint, but shouldn't that be negative pressure i.e. vac?

In any case, that little nozzle doesn't appear to do anything from either direction. It's only operating as a plastic union in the vac hose on my bike.

 

[Stephan]

My XS1100 has a similar hose without a plastic connector that goes from the intake on cylinder 2 to a mechanical vacuum advance that physically rotates the pickup plate to advance the ignition timing, so I think that you are right, it is simply a plastic union for the two hoses.

 

[maleko89]

The arrow should point to the pressure sensor. It does matter as it smooths out the signal similar to what the restrictors do for a carb sync tool.\

Mark

 

[Spyglass]

Ah...so it smooths the vacuum pulse. That makes sense. Thanks!

I was about to remove it.

Once I get my carbs back from Eric (Traumahawk), I'll put a gauge on there to check the difference upstream and downstream of that little nozzle.

 

[Stephan]

The arrow should point to the pressure sensor. It does matter as it smooths out the signal similar to what the restrictors do for a carb sync tool.\

Mark

Maybe that's the difference between an electronic pressure sensor and a mechanical one that does not need the vacuum pulses smoothing out.