GS850G Carb QUESTION--new guy

[Anonymous]

I saw a Q/A about carb hoses in the OLD Q/A SECTION, it is the second one down, from March 2000.

This is my first question, awesome board! I'm a college student from WI!

I just got my first GS ever, an 850G. The two hoses (which I assumed at first were vents???) between 1&2, and 3&4 were missing. When the petcock is turned "PRIME" (with engine not running) the t-connection between 3&4 starts leaking a LOT of gas all over.

To remedy this, I put hose between the two nipples, but as the Answer said they were vents, this seems like the wrong idea.

ANY IDEA what's Wrong???


THANKS FOR YOUR HELP GUYS!


THe original idea was to clean up the bike and sell it, but this has really slowed down my efforts and discouraged me. It is currently for sale as-is, but I'd MUCH Rather get it running smoothly and figure this out. I have pics if desired

[frosty5011]

Mike,

[Anonymous]

any ideas?

any idea why it leaks all the gas?

[humhead]

Possible explanation

Many GS bikes have vacum operated petcocks. When in the on position, gas flows only when vacum is present at the petcock. This is provided by a hose from one of the carbs. The prime position by-passes this feature and allows gas to flow all the time. It's useful for re- filling the float bowls if you run out of gas. Does the leak stop when the petcock is in the on/run position? If so all should be ok. There's no reason to switch to prime unless the carbs are empty.

Terry

[Anonymous]

on/prime

it only leaks when prime...so basically, when the bowls fills w/gas (quickly) it overflows? Is that what's happening?

don't think the floats like they'd been maladjusted...

thanks for all your help guys!

[earlfor]

Re: any ideas?

The bike has a vacum operated petcock. The petcfock will allow gas to flow when set to run or reserve. Normal position is the run -position.
Prime bypasses the vacum shutofff and allows fuel to flow directly without vacum or the engine running. Prime is intended to fill the float bowls if you have run completely out of gas. Usually, in this instance you would switch to prime for about ten seconds to fill the float bowls and then return the selector to run. In the prime setting, fuel will flow until the float needles shut it off, if the float needle seals leak, or are stuck/sticking, then fuel will never stop flowing. If the float levels are set too high, fuel will continue to flow when set to prime and overflow from the overflow tubes. It will also flow into the crankcase oil in this condition.

Earl

any idea why it leaks all the gas?

[Anonymous]

Have you had the bike running or are you still at the stage of "getting it running stage"? If the floats are working properly gas should not leak regardless of the petcock being at ON or PRI position.

A possible quick solution may be to put the petcock to the PRI position, then GENTLY tap the bowls of the leaking carbs with a hammer or wrench. What you are trying to do free a stuck float so that is can close the needle and stop the leak.

[Anonymous]

agreed!

I am still trying to get it running...this happened before and after I took the carbs off for cleaning. I'm no professional, but I've cleaned a fair amount of carb banks in my short time as a motorcyclist, and I don't understand how I could have missed a sticky float/needle valve.

I am away from the bike for a time, but perhaps I will drop the 3 & 4 float bowls and check to see that the floats move around ok. If it is not the float pivot at fault, then I will move up to the valve/seat area. Sound about right?

THANKS FOR ALL YOUR HELP GUYS!
This is an awesome web board

[Anonymous]

It could also mean that the float is not floating ( filling up with gas).

[Don Lobacz]

All it takes is one speck of dirt on the rubber tip of the needle to make the gas overflow (been there, done that, pulled hair because of it).

[Anonymous]

GS850 Carb Question -- new Guy

Please see the "Carb Cleanup Series" section of this Website for vent lines, fuel inlet lines and vacuum line to activate fuel petcock.

Generally, if fuel runs out of the carbs when petcock is in the PRIME position, the floats are stuck down or sinking, or fuel inlet needle valves aren't sealing properly to shut off the fuel after the carb bowl fills up.

Good Luck...

[Anonymous]

I had gas overflowing into the carbs and flooding the engine. Rebuilt the petcock, problem solved.