I did a search and read that it was a simulated electronic reserve. but what the hell does that actually mean?
further search mentioned something about the petcock doing something as well.
i was low on fuel the other day and flipped the switch not knowing if it really did anything. when i was cleaning out my tank i also noted that there is nothing electronic about my petcock. just a simple "on" "off" valve for when you remove fuel lines.
so if the petcock doesnt do anything. What's going on in there?
On the fuel pump bikes it shuts off the pump so you have to go to reserve to start the pump again. Sounds screwy but that's YAMAHA for you.
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.
At what point does that occur? Right when the light turns on? Or after its been on for a little?
Thanks for the proper info btw!
It happens after the light turns on. You still can go for a while with the low fuel light.
Quote from: wakdady on April 24, 2011, 12:45:11 AM
At what point does that occur?
.....the point when your bike starts running on 2 cylinders COULD BE exactly when you don't want this to happen... Like when you're passing a string of RV's on a uphill grade with opposing traffic coming at you....Yea, that is exciting.
With a working fuel gauge, low level light and a trip odometer, do you really need a reserve switch?
Thanks for asking the question. I have be trying to figure it out myself and kept forgetting to ask myself.
What year FJ are we talking about? They're not all the same you know.
Let me change my statement. The 89/90 cut fuel pump power the 91 and up just might shut down a coil.
I'm glad my 86s works. The light comes on just as I need to turn reserve on. So far so good 5000mi later and it still works, tried it the other day. :dash1:
If it's there, it will be hooked up. It might save me a dumb shit of the day award, I get enough of them lately thank you.
Bob W
Quote from: tqmx1 on April 24, 2011, 09:17:07 AM
Let me change my statement. The 89/90 cut fuel pump power the 91 and up just might shut down a coil.
I have also wondered how this switch works, I know some have posted they have disabled this function. I have a '89 so what needs to be done to the switch/bike to disable it? I normally just watch my miles to know when I'm low on fuel.
Quote from: WS on April 24, 2011, 12:32:16 AM
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.....
Quote from: Pat Conlon on April 24, 2011, 02:28:52 AM
Quote from: wakdady on April 24, 2011, 12:45:11 AM
At what point does that occur?
.....the point when your bike starts running on 2 cylinders COULD BE exactly when you don't want this to happen... Like when you're passing a string of RV's on a uphill grade with opposing traffic coming at you....Yea, that is exciting.
With a working fuel gauge, low level light and a trip odometer, do you really need a reserve switch?
cool.... im guessing i found my flaw.... chuckles... my light comes on but its only when it irratates me that i hit my res switch.... havnt had it drop out or cut out on me..... only once when it was dead empty and within the last 10 meters ( 30 odd feet in old speak :blum1:) of the servo. agree with ya pat... watch the little numbers go round and know the mileage/kilometerage is always good.... also as my fuel needle has popped itself all the way round to the other side of "E" and i couldnt be bothered fixing it for the gazillionth time..... so im just a numbers guesser now..... interesting read this to know what happens i actually thought it just switched off the pump and turned it to gravity/ vacuum feed
Quote from: RichBaker on April 27, 2011, 07:38:37 PM
Quote from: WS on April 24, 2011, 12:32:16 AM
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.....
Agreed!
Harvy
Quote from: Kopfjaeger on April 27, 2011, 07:52:04 PM
also as my fuel needle has popped itself all the way round to the other side of "E" and i couldnt be bothered fixing it for the gazillionth time.....
Neil, I have a fuel gauge here if you want it........its still on the right side of the stop....... removed it when I installed the Acewell dash.
Harvy
: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 (popcorn)
Quote from: RichBaker on April 27, 2011, 07:38:37 PM
Quote from: WS on April 24, 2011, 12:32:16 AM
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
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
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.
I just leave it on reserve all the time and watch the miles....
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
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
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?
:mocking:
Arnie
Quote from: FJmonkey on May 05, 2011, 08:55:32 PM
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. :sorry:
(It's good Karma), there it is I said it. And we needed it. :diablo:
Bob W
Quote from: Arnie on May 05, 2011, 08:35:16 PM
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
Quote from: wakdady on May 06, 2011, 06:52:39 PM
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
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 :biggrin:
KOokaloo!
Ha ha! "Brutus"?
love it.
Quote from: fb747 on May 09, 2011, 01:35:29 AM
Ha ha! "Brutus"?
love it.
yup named by the builder
(http://i47.photobucket.com/albums/f198/Racerman27410/Brutus2.jpg)
KOokaloo!