Questions from a new owner

[Super]

So my new to me 86 FJ1200 is on the road, aside from more vibration at certain revs than I was expecting it runs beautifully.  I really don't understand the fuel reserve.  I drove it last week until the fuel gauge (which seems to work as designed) ran a needle width below the empty mark.  The red fuel light did flicker on and off a few times but did'nt stay on.  In a perfect world I thought I'd drive around with a couple litres of fuel in a can strapped to the bike somehow to see what happens when it sputters out.  I did finally chicken out and went to refuel.  I could see very little fuel in the tank, in fact the float was sitting on the tank bottom.  I put 17.5l of fuel in the tank, so in a 22l tank I had 4.5l or about 1 imperial gallon left.  Is there a separate float in the tank that triggers the low fuel light?  What happens then?  Does the ignition cut out, requiring me to turn on the reserve switch or does the light just come on and at some point the bike will run out of fuel until I trigger the toggle switch into the up or reserve position?  I did have the tank off and didn't notice a separate float for the red light.  My bike does have the electric reserve solenoid, but as I said I was too chicken to run the bike dry and be left on the side of the road if the reserve solenoid isn't working as it should.

Anybody with first hand experience as to what happens and how the system works?  If the red light is triggered by the fuel sender float, then I have an issue as the float couldn't drop any farther, the tank was that low.  Also, the tank must have some pretty deep crevasses at the lower rear edges to hold 4.5l of fuel!

Tanks, I mean thanks,

Happy Thanksgiving....

Dave

[Pat Conlon]

The float only affects the fuel gauge, not the low level red light on the cluster. There is a separate sensor on the float assembly that activates the low level light.

Dave, do you have an Owners Handbook for your '86? See my signature line, download one for free.
In there you can read about your reserve switch functions. 

Cheers

[balky1]

I noticed on my '85 that FUEL light gets on pretty fast and when I refuel I can't get more than 15-16 liters in. Strange thing. Even when I was trying the same thing you were, with getting it dry, driving almost 70 km on "reserve" before also chickening out, I couldn't get more than 17-18 liters in.

[FJmonkey]

Dave, having an '86 myself I think I can answer your question(s). The fuel light should come on when you have about 3 to 4 liters left. It then gets brighter as the fuel gets lower. At some point the fuel is electronically shut off at the petcock. To resume fuel flow you flip the reserve switch, this bypasses the electronic reserve function and lets you run the tank dry. So once the low fuel light comes on it should stay on till you add more fuel. Your fuel not cutting out suggests a faulty petcock or it was bypassed by a previous owner/mechanic. Check under the tank to see if your petcock has wires connected to it. Or you may not have run it dry enough, but it sounds like you did if you saw the float touching bottom. But with a 4.5l left, it may not have cut out yet.

FYI, a known weakness of the '86/'87 petcock is the vacuum diaphragm. Pull the vacuum line off the carb intake boot, with the fuel line still connected, suck on the vacuum line. It should feel like a straw that is plugged solid. If you can suck air and have to keep sucking to maintain a vacuum then your petcock or vacuum line is failing. Try again with a known good vacuum line. It may still hold enough vacuum to work, but at some point it will leave you stuck away from home. I replaced mine with an '84/'85 petcock. No reserve function, has a Prime position and costs less than the '86/'87 unit.

[ct7088]

I have an 86 tank on my 85 FJ. When very little was left in the tank I  put in 19.68 liters(5.2 gallons). Looking in the tank no fuel was visible without moving the bike side to side. I usually get 40 miles to the gallon with the mid octane no-ethanol gas.

[ct7088]

Also my 85 the fuel light goes on and off for around thirty miles. When the light stays on while moving there is still about a gallon left.

[Super]

Ok thanks.  I did have the tank off and everything is original.  I had a 900 with the vacuum petcock which I rebuilt so I'm familiar with the shut off operation and how the tall and short in-tank spigots interact with the run, reserve and prime positions.  I do have the owners manual but it lacks information on what actually happens when the fuel level drops.  I didn't see any other float mechanism in the tank other than the one for the gauge so I'll accept that at some point when the float is sitting at its lowest spot, something triggers the low light to illuminate.  Safe to assume when the float drops, the light illuminates and the "module" triggers the fuel tap to make it draw from what was normally the "run" spigot on older systems?  That would make the engine starve for fuel at some point when the level drops below the higher spigot.  Toggling the reserve switch then cuts the power to the tap, it resorts to the lower spigot (the old reserve spigot) and off you go until the tank runs dry?

I'm going to bring a couple litres of fuel with me towards the bottom of this tank and see what transpires.

Dave

[FJmonkey]

Dave, the '86/'87 petcock does not a high/low drain set up like older manual petcocks. There is a sensor (not a float) that when immersed in fuel stays below a certain temperature, as the fuel drops this sensor is exposed and actuates the low fuel light. As the fuel drops lower the sensor reaches full temp, the fuel light transitions from dimly light to full bright, after that it actuates the solenoid in the petcock stopping fuel flow. Moving the reserve switch to RES position turns the solenoid off and fuel will flow till empty.

Here are some pics of the sender, you can see the little canister with a wire coming out the top. This drives the low fuel light and possibly the electronic reserve.

http://www.fjowners.com/index.php?topic=6924.30

[Super]

Thanks, I needed to know how the system works. I'm going to run it down again and see what happens.

Dave

[Super]

Here are some pics of my bike,purchased this spring from the original owner with less than 20k.  Still wearing the original tires.  Had been stored with a full tank for over 10 years.

Carbs were a mess:
Made my own baking soda blaster, here are the results.  Had to purchase new needles and seats, plus new bowl gaskets:
Back on the bike:
Balanced nicely:
The chin fairing was missing the small chunk aft of the securing bolt.  I made a new "ear" by using the other side as a pattern, cut out a sheet of 1/8" abs, glued it all back together using melted lego and MEK with steel window screen to beef up the repair.  I blended the repair using Hyundai pearl white from Canadian Tire, VERY close match to the "Silky White" and the can of paint cost me $11.00:
Installed new tires, slave kit, flushed all the fluids etc and drove it some this summer:
I need to replace the pads and have bought kits to do all the calipers this winter.
Also need to take the fairing pod apart, the previous owner dropped the bike on the left side and something in the instrument pod must be bent as there is an really annoying "buzz" at around 4k that vibrates the speedo/tach cluster.
Cheers.
Dave

[Pat Conlon]

Beautiful Job Dave. A very nice solution on the Chin Fairing!

Yep, the instrument cluster buzz is common. While you have it out, consider replacing *all* the cluster's light bulbs. Get the LL version of the oem bulb or several folks have had success using the LED version, (excepting the low fuel light which needs to dim and brighten)

Don't over torque the (2) 10mm bolts holding the cluster to the fairing stay (aka sub frame) They are very fussy.


The old girl is very fortunate to have an owner like you....Kudos!

[FJmonkey]

This is FJ porn, a very clean looking '86. I hope to get my '86 looking this good. Awesome dude...

[Super]

Never tried to see if the noise is there on the stand.  The stay that supports the fairing was a bit bent from the fall.  If I hold the speedo pod with my left hand while accelerating through the 4k range, I can stop the buzz.  It seems that the pod is too close to the fairing.  Seem to recall some foam glued to the pod, perhaps these need to be refreshed and some other adjustments made to the stays.

[rktmanfj]

FWIW, I was able to eliminate a lot of the fairing buzz by removing all the inner panels, and applying soft plastic auto door moulding to all the edge contact points on them, including the instrument panel opening... some of the remainder was remedied by gluing the edge of the vent screens with weatherstrip adhesive.

[Mark Olson]

Oh yeah the buzzing will drive you crazy..
one time I stuffed some memory foam from an old mattress topper between the windscreen and the top of the instruments . That was 3 yrs ago and it is still there to stop the buzzing. I need to go thru all the fasteners and put insulators between the contact points . Maybe this winter .