ECU? and vacuum hose

Information and questions on GL1200 Goldwings (1984-1987)
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Posts: 60
Joined: Tue Sep 21, 2010 3:42 pm
Location: Desha, AR
Motorcycle: 1987 GL1200 A Aspencade Sadly wrecked 2-25-12

1989 Honda GoldWing GL1500

ECU? and vacuum hose

Post by noeleo » Fri Apr 22, 2011 8:48 pm

Yseterday, while my GL1200A was down awaiting fork seals ( :D yes, I did them myself :D ), I dropped one of the washers that goes between the upper and lower spring (stock set). I wound up having to take off the lowers and remove the false tank to finally locate it. While looking, I noticed a vacuum hose that came from the carburetor area and went to a tee. One side of the tee went to the ECU (I think that's what it is), and the other side went about 4" and then terminated to what looks like a check valve, which I would assume, is in case of a backfire to vent the pressure instead of blowing the sensor in the ECU. So, with my limited understanding, I would figure that the line going to the ECU is for kind of like a vacuum signal that the ECU monitors and would adjust the ignition timing, right? Anyway, the source side of the tee had a cracked line on it, so I just cut the split off and reconnected the hose to the tee. WOW, what a difference!!! The OldWing runs like you gave her a shot of adrenaline. Lots more throttle response at lower RPM, and seems like more seat-of-the-pants kick when you roll the twisty thing with your right hand. Am I in the right area of thinking with the signal idea, or did I just find a fluke? Going for a long ride with the wife tomorrow, and will see if this affects my gas mileage. I lost some mileage after the recent carb synch, but hope that this will bring it back. Maybe, I'm just wishing something that won't happen, but it never hurts to hope.

Next project, rebuild the rear shocks. Any ideas where to get seals?

Ride your GoldWing no faster than your angel can fly.

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Posts: 4
Joined: Mon Dec 14, 2009 8:56 pm
Location: Batesville, AR
Motorcycle: 1984 GL1200A
1989 GL1500

Re: ECU? and vacuum hose

Post by shylow101 » Mon Apr 25, 2011 5:27 pm

Noel, good find and fix on the vacuum leak. now that that is fixed you will most likely want to re-sync the carbs again. syncing against a leak cannot be the best situation. Tho with the weather like it is we may need to trade the wings in on some paddles LOL.

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