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[Stevis05]

Hello everyone, just got an 85 fj1100. Got in trade for reassembling a jet ski. Any how, I got it running but it’ll need some work. I am in need of a picture or description of the carb hose routing, more specifically: there are two plastic barbed fittings between 1-2 and 3-4 carb. Mine has nothing connected to these are they vents? Any help appreciated. This is like my umpteenth Yamaha and this thing reminds me of my 87 srx 250. Miss that little thing....

[Pat Conlon]

Hello Stevis, welcome aboard, yes, you are correct. Those 2 T’s (between carbs 1/2 and 3/4) are your fuel bowl vents. They have hoses connected to them approx 12” long and run to the back of the engine.
You could leave the hoses off, as many do, but I would not recommend it. The reason being that if you get a stuck float and the float bowl overflows, the fuel will come out the vent T’s and you do not want that fuel dumping onto the top of your hot engine cases. With the 2 hoses installed and routed to the backside of the engine case, that fuel will just drop onto the top of your exhaust collector box.....much safer....not really.
It is important that these float bowl hoses not be kinked or pinched.

See if this helps

Hose #38 are your float vent hoses
The 4 smaller hoses #6 and #29 are your choke vent hoses...they also run to the rear of the engine case.

One thing that is important to pay attention to is the *proper* routing of your fuel line hose.
We discuss this here: http://www.fjowners.com/index.php?topic=18286.0

Cheers

Pat

[Sparky84]

G’day and Welcome Stevis

Congratulations on your new purchase, you won’t be disappointed  


Cheers
Alan

[Stevis05]

Thanks for the info. The bike has k&n oval chrome faced air filters so the oem filter and box is gone. Very helpful. The tank pet cock came to me separate from bike, so fuel lines were dangling. I may not need to route them as pictured because of all the extra space my bike has with the air box removed. I was told the pet coco needs a new oval shaped gasket. The push in strainer is malformed and doesn’t fit quite right so I may remove it in favor of an inline filter. I’m not sure if I have a carb leak cause I hooked up a gas can and gravity fed the carbs to get it to start and noticed fuel dumping out under the carbs. I was thinking it was cause I made a vacuum suction and hooked up the fuel line to carbs and the bike wasn’t on so the fuel was dumping in and overflowing. I’m gonna pull the carbs and take a look anyway just to be sure. Bike seems pretty complete but missing a few things: lower cowl, caps over fork tubes, no front flashers, front fender broken, rear flashers broken, chain guard broken. Fuel cap and ignition are “key less” ie; someone jammed a screwdriver in and turned them bike has 47k mi on it which seems a bit high but I don’t know history on it so may be alright. It’ll need a rear tire. Has a Vance and Hines exhaust. Sounded good when it started. It’ll take some work but I got it basically for 3 hours of assembling a jet ski in the hot sun. Will be checking In more for more help I’m sure. Thanks again

[Stevis05]

Anyone know off hand what size ID the main fuel line is? Trying to source an inline fuel filter thanks

[FJmonkey]

10 mm, but a filter may be too restrictive for normal use. Gravity feed needs a free flow when the tank is low. Low fuel in the tank = low pressure. I recommend getting a new petcock once you get the age issues sorted.

[Stevis05]

Ok that makes sense. But doesn’t the Pet cock have a fuel pump built in? I thought that’s what the smaller hose was for, coming from the 1 carb boot. My thought process was that when engine turns, the suction goes thru the tube to create a pulse to pump the fuel. This is how my Yamaha jet skis are. There’s a small tube from the intake manifold to the fuel pump, that creates a suction repeatedly or a pulse, that then pumps fuel to the carbs. Or is this setup on the fj just to create a prime?

[Stevis05]

This is what I meant by doesn’t fit right. The plastic has misformed

[FJmonkey]

Ok that makes sense. But doesn’t the Pet cock have a fuel pump built in? I thought that’s what the smaller hose was for, coming from the 1 carb boot. My thought process was that when engine turns, the suction goes thru the tube to create a pulse to pump the fuel. This is how my Yamaha jet skis are. There’s a small tube from the intake manifold to the fuel pump, that creates a suction repeatedly or a pulse, that then pumps fuel to the carbs. Or is this setup on the fj just to create a prime?

The smaller vacuum tube allows the petcock to open and close with engine vacuum. Its a safety thing. No fuel pumps till 89...

[fj1289]

The petcock uses the vacuum line as an automatic shut off.  It does NOT operate like this vacuum operated pump:

https://www.denniskirk.com/mikuni/single-fuel-pump-df44-227.p1609.prd/1609.sku?utm_source=google&utm_medium=csecid=6821162156&aid=76472566741&keyword=831081073363%3A%3Apla-831081073363&kid=831081073363&gclid=CjwKCAjwxqX4BRBhEiwAYtJX7Y1YX6NvRjZiMomig5671Kk02hhMLSXpsyRFIG2pozBON3tqjMzI5RoCQakQAvD_BwE