Vacuum Pipe from ECU

[tdm34]

Hi All, Me again, still working through my 87 FJ1200, thankfully very nearly finished, came across another issue, the ECU has a vacuum hose on it it's about 6 inches long and it's connected to nothing! The manual says it should be connected the the vacuum take off on the no2 inlet rubber.

Questions

1: What problems will it cause in it's present state, also I discovered that the bike had been fitted with a V&H advancer, would that have anything to do with the pipe being disconnected, the no2 inlet rubber has a bung covering the vacuum take off, but it's different to the others.

2: Where would I be able to get the hose to connect it all back up.

Regards
Rob

[T Legg]

The vacume connection is to change the timing on decceleration for emission purposes. There is no loss of performance if it is not used. If you want to reconnect it you just use a longer hose and connect it directly to the barbed fitting on your intake. I'm not familiar with the v&h advancer but I would bet that is why it is disconnected .

[Old Rider]

I think its only the USA models that have the vacuum advance tube .Most European models does not have it.

[Pat Conlon]

Yep, what Travis said...

If you do want to hook the vacuum line back up, first make sure the diaphragm in the ignition box does not leak. Do the suck test. Connect a hose on the ecu vacuum port and suck on it...if you can draw air your diaphragm in the ignition box, it leaks. If so, Don't connect the the line back to your carb.....you will be drawing in un metered air into your #2 cylinder. (Lean)
That's probably the reason the PO disconnected the vacuum line to begin with....it leaks from a bad diaphragm.

Here you can read all about it:
http://www.fjowners.com/index.php?topic=11690.0

There is no loss of performance from disconnecting this vacuum line.
Be sure to properly cap off the #2 vacuum port. Do not use cheap vacuum caps, they melt from the heat, instead use the heavy rubber oem Yamaha vacuum caps.

Hope this helps...