Reserve switch. What does it actually do?

[Kopfjaeger]

 :good2:that'd be great Harvey. PM me let me know how much etc. always up for new bits.   Now i should just get motivated and wash her.....lol

[moparman70]

The fuel sending unit gives a signal to the black box which turns off one ignition coil. The bike starts running on two cylinders and it feels like you are running out of gas. By switching to reserve you turn on the coil again.

This is INCORRECT.... on all years FJ(except 84 & 85), the fuel flow is shut off, 86/7 use a solenoid at the petcock, 88-on shut off the pump.....

all above I believe is correct ....I believe the 86/7 does cut off the gas-- these bikes and earlier are gravity fed -- I examined my 86 and the petcock opens the flow when you turn the bike on and the engine creates the vacuum.... for normal operation and when the fuel light came on really bright it shut off the gas.  The vacuum gets cut off somehow ( solenoid --I don't know ) and then hitting the reserve switch allow the flow to happen....simulated reserve.

sc2

[DailyDriver]

I too wondered how the reserve switch worked at times. Since this thread appeared I've been searching. I read one web page that says power is cut to one of the coils. However, the wiring diagram for my '90 model shows the reserve switch wired to the fuel pump relay. I believe the correct answer is the fuel pump based on the diagram. FWIW

[cadmanmadman]

What does it do?......Annoy you.
It switches over to reserve when you have more than a half of a tank left.
When it starts to buck and spit becuase it thinks your gas is low, and you think you have alot of gas left, you think the worst and look for any other problem.

[cadmanmadman]

I just leave it on reserve all the time and watch the miles....

[weymouth399]

Guess I'm lucky, mine works perfectly. light starts to come on, soon as it pretty much stays on she'll start to sputter.
Turn the switch on, and then go fill up. I have run another 10-12 miles on reserve. I always put 4 to 4.25 gallons in her, I think that's most of it.

Bob W

[Arnie]

Mine works as expected too.
About 50kms after the needle is on E, the fuel light starts to flicker then stays on solid for a while.
When it starts to miss and buck I switch to reserve and have (more than) another 50kms of fuel left.
Depending on how I'm riding I get between 325 and 400km per tank.

Cheers,
Arnie

[FJmonkey]

I noticed that while I am riding and feeling quite frisky in the SoCal canyons some riders coming the other way will motion to be cautious, Hands waving down, Hands patting top of helmet etc..... So I switch to "Reserve", then my riding style totally changes and I am the most mellow rider around. I even waive to the LEO's pointing speed guns at me. I know I am in the slow and reserved groove like I have no speed agenda...It works for me. Does this work for you guys? 

[Arnie]

 

Arnie

[weymouth399]

I noticed that while I am riding and feeling quite frisky in the SoCal canyons some riders coming the other way will motion to be cautious, Hands waving down, Hands patting top of helmet etc..... So I switch to "Reserve", then my riding style totally changes and I am the most mellow rider around. I even waive to the LEO's pointing speed guns at me. I know I am in the slow and reserved groove like I have no speed agenda...It works for me. Does this work for you guys? 

We (NEFJR particapants) do that for the week after a sucsessfull rally, just to calm the speed gods.
(It's good Karma), there it is I said it. And we needed it. 

Bob W

[wakdady]

Mine works as expected too.
About 50kms after the needle is on E, the fuel light starts to flicker then stays on solid for a while.
When it starts to miss and buck I switch to reserve and have (more than) another 50kms of fuel left.
Depending on how I'm riding I get between 325 and 400km per tank.

Cheers,
Arnie

250 miles! out of a tank! Jeez! i wish i was that lucky

[Arnie]

250 miles! out of a tank! Jeez! i wish i was that lucky

Well, it was a one time thing and as I coasted to a dry tank & carbies stop saw that I'd covered exactly 400kms.  I was lucky that I was near enough to call a friend who came with a gal can of petrol to save me :-)  I then filled up the tank for a total of 22.5 Litres.
350kms (217mi) is a "safe" distance for me when in cruise mode.

Arnie

[racerman_27410]

if i ride like grandpa i could stretch a tank of fuel out to 200 miles on the stock bike...didnt run out but that light was glowing real bright for a long time....... now my rear ride height increase has slightly affected how much fuel is actually available to me from the tank.... i can safely go about 170 miles if i ride easy....... but Brutus's power is quite addictive so let's just say 150 miles and its time to get some gas ...... if i really hammer on it...  120 miles and i'm on fumes   


KOokaloo!

[fb747]

Ha ha! "Brutus"?

love it.

[racerman_27410]

Ha ha! "Brutus"?

love it.

yup named by the builder




KOokaloo!