is it possible to bypass the reserve switch system on a 91 3xw

[jono]

my bike is coming along fine it just passed its warrant of fitness certification ,ive put a paint job and decals on it ,sorted the tuning problems   which was i think bad cv rubbers and air box leaks with pod filters and new slide rubbers but my bike was originally a abs model and someone removed the abs and all the related wiring and i don't have a low fuel warning light anymore.  But what I've noticed is if i leave the reserve switch in the on position even with over half a tank of fuel the motor runs badly like its lean but if i leave it switched to reserve it runs fine what i would like to do is remove the switch completely ,my fuel gauge works so im quite happy to rely on that. As the bike runs like crap if the switch is in the wrong position what i want is, key on ,fuel pump on, gauge telling me fuel amount with no sensor changing something due to fuel level ! is this possible???

jono

[CutterBill]

To answer your question, yes... it is possible. And quite easy. Pull the switch housing up out of the fairing so you can access the wires on the switch. What you want to do is connect the two wires. With the switch in the ON position, the switch is in the open position. With the switch in the RESERVE position, the switch is closed.

Sounds like that for some reason, the pump relay always thinks the tank is almost empty and turns off the fuel pump.  Flipping the switch to RESERVE turns the pump back on.

But why is the pump relay confused? One clue might be the fact that a previous owner removed the ABS system, and he might have done it incorrectly. Remove the seat and look back into the tail section. There is a gold-colored shelf which holds the ABS computer, the fuel pump resistor and the ripple-smoothing capacitor. Is the resistor still there and connected? It is a white or ivory colored ceramic block, about 3/4-inch square by about 3 inches long. It will have a push-on terminal on each end.  I'm guessing that since it sits next to the ABS computer, the PO wrongly thought it was part of the ABS system and removed it. Check that it is still there and connected.

While you are there, check that the capacitor is still installed. It's a black cylinder about 1-1/2 inches in diameter and about 3 inches long. Two wires come out of one end. It's sole purpose is to smooth out the voltage fluctuations (ripple) caused by the alternator so it won't affect the fuel system or anything else. But it should be there. 

And your bike has a low-fuel level light? Hmmm, that might be a Kiwi requirement. The USA bikes don't have that light. (Oddly, the Owners Manual states there IS such a light, but it's not on my ABS bike, nor is it shown in the electrical diagram in the shop manual. Strange...

Speaking of wiring diagrams, go to the Files section, then Electrical. Look for my post titled Current Flow Diagram. Open and make sure you get the post labeled Rev 2. Download and print those files.  Hope this helps...
Bill

[jono]

thanks bill
both the ivory colored ceramic block and the  the capacitor are  there and wired in i will join the wires together and see how that goes the fuel pump is brand new

and it runs fine when its switched to res so i hopefully no more problems

thanks

jono

[jono]

as an after thought what would happen if i wired the fuel pump directly to key wih no sender ? so basically key on fuel pump on key off fuel pump off

jono

[RPM - Robert]

You lose the safety function. If it does not pick up the running signal, the fuel pump only stays on for a few seconds. That way if you crash or drop the bike the fuel pump will shut off and not dump all the fuel.

[jono]

thanks for that info Robert ever since ive got this bike up and running ive always thought at times it runs lean i took the valves out of the petrol cap, new filter and fuel pump and as i stated in  my previous post it seems to run better when its switched to reserve i think i will hot wire the fuel pump temporarily just to see if it makes a difference

jono

[yambutt]

After 5 yrs of not having my reserve switch work in the on position on my 92 fj I finally found and fixed the problem. It wasn't the fuel pump relay, wasnt assembly relay and wasn't my fuel sender unit....what it was is that ceramic resistor and the short wire came disconnected from the resistor so I lengthened it a little and made a extremely  tight spade connection and after at least a half dozen tries I finally fixed the problem thanks to the comments on this post.
It had become a obsession of mine to fix that damn thing...THANK YALL SO MUCH. The ceramic resistor is screwed down to the bracket under the tail section, very easy to get to, its a 70 ohm resistor so if its still connected pull 1 wire off and ohm it out to see if the resistor is still good. I never saw a capacitor anywhere near there and had taken my abs off at least 7 yrs before I had this problem, i still have my abs unit and computer in my storage in a box together and no capacitor in there plus id never just unplug or disconnect a capacitor thinking it was with the abs unit but I never found that on or off my bike....maybe I missed it but all I know is once I made the connection back to the resistor the on/res switch works perfectly now.

[yambutt]

thanks for that info Robert ever since ive got this bike up and running ive always thought at times it runs lean i took the valves out of the petrol cap, new filter and fuel pump and as i stated in  my previous post it seems to run better when its switched to reserve i think i will hot wire the fuel pump temporarily just to see if it makes a difference

Just leave it in the reserve position if you don't have the need to fix it, those switch contacts last forever but if you don't trust the contacts you can either solder the wires together on the switch or cut them both off and twist them together then silicone beenie the connection and tape it to protect it but I'd just leave it on the switch In the reserve position

[yambutt]

My 92

[jono]

Ive checked the whole loom and im sure all connections are good i now know what the problem is, but not whats causing it ,the fuel pump is turning off .
the bike will start and run with the fuel pump disconnected but it runs like shit like its been doing randomly since i bought the bike ,the only thing i know at this stage is
when it stops working there is a click in the front nose cone witch i presume is the small black box on the right side of fairing sub frame (3xw ) and when i turn the key and restart its fine i just don't know whats causing it to click and turn the pump off Ive just added a  new fairing and screen,new mufflers,and a new pirelli night dragon rear ,and ive got 3 weeks paid leave so Yee-haw! if the tanks over half full it runs fine so im gonna ride it hard for the summer and sought it after the break

jono

[wainot-Phil]

Just asking how is it that you can 100% tell that the Fuel Pump is the Problem and that the Fuel Pump is not working causing the Bike to run badly , once the Fuel Tank gets below 50% full

[jono]

Ive had a problem with the way the motor runs ever since i got the bike and as i said earlier in this thread i decided to run the fuel pump from the battery and at first i tried wiring from a plug that was live when the kill switch was on but had no power when the kill switch was off and i noticed that i wired it up there was a click from somewhere up by the speedo and it ran rougher than when i connected the pump to the battery ,then i tried starting it with the fuel pump unplugged and its starts and runs poorly  just like it did after it clicks which  leads me to believe the fuel pump has been cutting out since i first noticed a problem.  I thought was it was running to lean. if i connect the fuel pump directly to the battery it idle and runs well

jono

[yambutt]

So in reserve position it runs good all the time but in the on position as soon as you hear something click it runs
poorly.....id meter the voltage at the pump when it runs poorly just to see if you have a voltage drop at the pump. Sounds to me your having a voltage drop to cause the pump to run poorly cause if the pump was at fault it would run poorly hooked up to the battery also. Also if that ceramic resistor is going bad the resistance could be fluctuating way above the 70 ohms which would cut the voltage down going to your pump while the res switch is in the on position

[wainot-Phil]

Ive had a problem with the way the motor runs ever since i got the bike and as i said earlier in this thread i decided to run the fuel pump from the battery and at first i tried wiring from a plug that was live when the kill switch was on but had no power when the kill switch was off and i noticed that i wired it up there was a click from somewhere up by the speedo and it ran rougher than when i connected the pump to the battery ,then i tried starting it with the fuel pump unplugged and its starts and runs poorly  just like it did after it clicks which  leads me to believe the fuel pump has been cutting out since i first noticed a problem.  I thought was it was running to lean. if i connect the fuel pump directly to the battery it idle and runs well

jono

What about leaving the Fuel Pump plugged in and also hooking a volt meter up to the fuel pump wires, Start the Bike ,Play with the switch off , on ,off on etc and see if the volts drop , If not it has nothing to do with your Fuel Pump Power supply ,,,Also  I would be very surprised if it has anything to do with the Fuel switch and not enough power getting to the Fuel Pump , Another option is to unplug your Fuel Pump and by-pass the Fuel Pump  with a little bit of pipe ,Just plug the 2 Fuel Hoses together ,,    The Bike should run just fine being gravity Feed with Fuel ,

[jono]

mmmm i don't like the idea of no fuel pump i'm pretty sure i runs lean when the pumps not working that's my problem Ive disconnected the reserve switch now and joined the wires which is now permanently on reserve and the fuel gauge is my only means of knowing the fuel level  and its running fine ,one thing puzzles me about the ceramic resistor when i got my bike the wires to it were corroded and one was broken so i re soldered it and i know its sound ,maybe its stuffed. Here's a question my 1tx gravity feed donor bike has got one as well what else does it do ? ,i might swap it out for the one on my 3xw and I'm definitely going to check the voltage on the pump and the resistor and the sender unit wires coming out of the tank the difference to how it runs with the pump working and not is dramatic ,its a brand new pump as well

jono