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Main Area => General GS500 Discussion => Topic started by: bikingreenie on August 21, 2005, 08:08:11 PM

Title: Fuel Shut-off??
Post by: bikingreenie on August 21, 2005, 08:08:11 PM
I just bought a 91 GS500. Been sitting for 2 years. I cleaned the carbs, tank and fuel valve, then re-assembled. Next morning there was a gallon of GASOLINE in the CRANKCASE(Which had happened while it sat for 2 years also).
IS IT NEEDLE AND SEAT, OR IS IT THE FUEL SHUTOFF VALVE? OR...DOES THE VALVE HAVE AN OFF POSITION? WHAT DOES PRI stand for?
Title: Fuel Shut-off??
Post by: aaronstj on August 21, 2005, 09:47:37 PM
(I don't actually have a bike - yet - but I think I've heard this answered enough times.  Someone will correct me if I'm wrong).

PRI stands for PRIme.  It lets gas run straight into the carbs, you use it when the system is dry (been winterized).  Some people also put their bikes into PRI when they run into high speed fuel starvation issues.  The ON and RES positions work on vacuum.  Letting the bike sit with PRI on is a bad idea, since the gas wil lruin all over everything.  

Or something like that.
Title: Fuel Shut-off??
Post by: rclz on August 21, 2005, 11:29:27 PM
That is a unusual problem, when the ignition is off no fuel is being pumped into the carbs, I don't see how that's possible. I would take my bike to the dealer if that was happening.
Title: Fuel Shut-off??
Post by: scottpA_GS on August 22, 2005, 07:16:51 AM
Yea, PRI will let fuel flow all the time, but if it is leaking you have a problem w/ the floats sticking  :thumb:

Even on PRI it shouldnt leak at all. If it does you need to check the floats  :thumb:

Also, turning it to the ON or RES position should shut off the flow unless the bike is running  :mrgreen:
Title: Fuel Shut-off??
Post by: maxwellf on August 22, 2005, 04:05:28 PM
Can anyone post an up close picture of their fuel shut off valve, so I can see which way my valve should be turned!! I can't figure out if mine is always on reserve... does that matter?  :dunno:
Title: Fuel Shut-off??
Post by: rclz on August 22, 2005, 11:43:49 PM
Yes it does, if you have a full tank of gas and have it on reserve your bike might run out of gas while you still actually have a full tank.
Title: Fuel Shut-off??
Post by: red_phil on August 23, 2005, 08:00:31 AM
The knob should have an arrow on it.

Up is 'Prime', pointing towards the front of the bike is 'reserve' and pointing down is 'on'.

I had this problem with my GSX400 it was due to a bad o-ring on the vacuum activated valve in the petcock and stuck floats.
Title: Fuel Shut-off??
Post by: Kerry on August 23, 2005, 02:30:54 PM
Quote from: maxwellfCan anyone post an up close picture of their fuel shut off valve, so I can see which way my valve should be turned!!
See this thread for annotated photos.
Title: Fuel Shut-off??
Post by: milo on August 23, 2005, 04:07:38 PM
Quote from: rclzYes it does, if you have a full tank of gas and have it on reserve your bike might run out of gas while you still actually have a full tank.

Uh, what?

I thought having it on reserve will let you go through that last gallon but otherwise run normally, the only danger being that if you DO run out of gas, you'll (naturally) have no reserve left??

Isn't it just that the reserve line is at a lower point on the tank?
Title: Fuel Shut-off??
Post by: milo on August 23, 2005, 04:09:25 PM
Quote from: red_philThe knob should have an arrow on it.

Up is 'Prime', pointing towards the front of the bike is 'reserve' and pointing down is 'on'.

Noobs reading this: Nota Bene that it might be different by year. On my 2001 pointing up is RES, pointing toward the rear is PRI, and pointing down is ON.
Title: Fuel Shut-off??
Post by: knowlsey on August 23, 2005, 04:35:04 PM
make sure the float bowl drain screws are sitting correctlt, they are slightly shamfered and if not sitting right the floats will drain straight on the engine
Title: Fuel Shut-off??
Post by: natedawg120 on August 23, 2005, 05:51:43 PM
Quote from: milo

Noobs reading this: Nota Bene that it might be different by year. On my 2001 pointing up is RES, pointing toward the rear is PRI, and pointing down is ON.


Thats how it is on my 05
Title: Fuel Shut-off??
Post by: Alphamazing on August 23, 2005, 06:33:00 PM
check the fuel shutoff valve. NOT the petcock with the lever, but the actual shutoff valve. It's under the tank, so you'll need to remove the seat, rear plastics, and take your tank off. It's a little dealy underneath by the hoses with a flathead screw for on and off. Make sure it's on.
Title: Fuel Shut-off??
Post by: 71buickfreak on August 23, 2005, 06:38:23 PM
I have heard of this problem on other suzuki's. The easy fix is real fuel shut off valve. keeps that from happening.
Title: Fuel Shut-off??
Post by: mjm on August 23, 2005, 06:44:28 PM
Quote from: natedawg120
Quote from: milo

Noobs reading this: Nota Bene that it might be different by year. On my 2001 pointing up is RES, pointing toward the rear is PRI, and pointing down is ON.


Thats how it is on my 05

2001 on are different than earlier bikes.
Title: Fuel Shut-off??
Post by: Kerry on August 24, 2005, 01:29:47 PM
Quote from: mjm
Quote from: natedawg120
Quote from: milo
Noobs reading this: Nota Bene that it might be different by year. On my 2001 pointing up is RES, pointing toward the rear is PRI, and pointing down is ON.
Thats how it is on my 05
2001 on are different than earlier bikes.


Have links to pictures gone out-of-style all of a sudden? :dunno:  Like I said eight posts back:

Quote from: KerrySee this thread for annotated photos.
Title: Fuel Shut-off??
Post by: ktrim on August 24, 2005, 01:39:29 PM
if you leave the percock set to prime and have a full tank or almost full,  the pressure from the gas is more than the floats can hold back so gas will constantly seep into the carbs,  its got to go some where so it will run out the over flows on to the engine and also drizzle out of the carbs into the cylinders, then it seeps past the rings and fills the crank case.  in short,  dont leave it on prime