Okay, putting the finishing touches on my 1990 fj1200... I replaced the speedometer cable and when I was putting the fairing back on I found a "stray" vacuum hose under the "vent" on the right side (in attached picture). I looked and looked although cannot figure out where it goes. Can any of you tell me what it connects to?
I have also noticed that my tach is now slow to operate... maybe the two things are related??
Thanks.
We can help if you tell us where the other end of that tube is connected. Sounds like you have a vacuum leak if not running properly.
The vacuum hose has nothing to do with the tachometer.
That vacuum hose should connect to a small little box up under the right side of the fairing. Yamaha calls it a "Boost Sensor"
It is designed to advance the ignition timing when a vacuum is applied. A few of the more knowledgeable folks on here have indicated it is only for emission purposes.
Running the engine with that vacuum hose disconnected will result in a lean air/fuel mixture in whatever cylinder the other end of that hose is plugged into. (usually cylinder #2)
Look way up under the right side of the fairing, attached to the fairing sub-frame the little box should have a small hose nipple on it.
The end that is showing in your photo attaches to the 'Boost Sensor'. If you remove your main fairing, it is located in the sub-frame near the headlight adjuster. The nipple on the sensor points down.
Here are a couple of links to help identify and locate the 'boost sensor' and hose.
It is #24 in the diagram http://www.partzilla.com/parts/search/Yamaha/Motorcycle/1989/FJ1200W/ELECTRICAL+2/parts.html (http://www.partzilla.com/parts/search/Yamaha/Motorcycle/1989/FJ1200W/ELECTRICAL+2/parts.html)
In this diagram the hose that you see could be the #31 hose. If you follow it, you can see that it does attach to the #2 cylinder intake boot. http://www.partzilla.com/parts/search/Yamaha/Motorcycle/1989/FJ1200W/AIR+FILTER+%28NON-CALIFORNIA+MODEL%29/parts.html (http://www.partzilla.com/parts/search/Yamaha/Motorcycle/1989/FJ1200W/AIR+FILTER+%28NON-CALIFORNIA+MODEL%29/parts.html)
Fred
Man you guys are good, I will thank you even if zoomjay didnt or just forgot!