no fuel flow

[mvalenti]

I tried to fire up the bike the other day and noticed that there was no fuel present in the glass fuel filter. I pulled the filter, and cleaned it out. verified there was gas in the tank, opened the petcock and fuel flowed fine with gas cap on or off.. Could the gas in the carbs gone to varnish since mid November? My bike is a 80 gs850 with 79 vm style carbs. Tank is not stock, and is vented. Petcock is not vacuum operated, more or less a ball valve. I took an airline and blew air into the overflow tubes, fuel tee, vents etc... I then connected everything up and opened the petcock still no flow... I pressurized the fuel tank with air (shop vac on blower side) and the filter filled. Any ideas why the fuel wouldn't flow?

-Mark

[Agemax]

if it needs pressure to fill the filter i would try removing that all together first.

[Steve]

Ditch the fuel filter. It is obviously too restrictive, probably from a car, which has a PUMP to push fuel through.

If you really insist on having an external filter (there should be one in the tank, at the petcock and another in each carb, at each inlet valve),
get one for a lawn tractor. Most of them have gravity-fed fuel systems, like our bikes.

.

[chuck hahn]

I would remove the carbs and see whats stuck in the bowls...

[chuck hahn]

The fact that he pointed out that the filter fills with fuel WITH the pressure from the shop vac added should tell you something right off the bat...that the fuel will go to thru the filter, but somewhere below the filter its got a restriction. So either the bowls are all gunked up with old fuel and the float needles are stuck or the fuel tee and / or transfer tubes are blocked.


While he has the carbs off he may as well redo the orings and dip them to be sure any passages arent clogged with crappy fuel chunks.
Take a wire and poke all the holes in the needle jets, the pilot jets, and the bleeder tubes.

[mvalenti]

Thanks for the input guys. I did do a complete dip/rebuild last year that included o-rings and went with those fancy brass t's and tubes.. Cant hurt to pull em again.

[chuck hahn]

Just a few months of sitting still with this crap ethanol will reeck havoc. You can probably reuse all the orings if you remove them carefully. Apply a thin smear of vaseline or other greasy lube to them when you put everything back together.

[Agemax]

Thanks for the input guys. I did do a complete dip/rebuild last year that included o-rings and went with those fancy brass t's and tubes.. Cant hurt to pull em again.

try it without the filter before you go pulling them apart again......

[gs850cafe]

Ditch the fuel filter. It is obviously too restrictive, probably from a car, which has a PUMP to push fuel through.

If you really insist on having an external filter (there should be one in the tank, at the petcock and another in each carb, at each inlet valve),
get one for a lawn tractor. Most of them have gravity-fed fuel systems, like our bikes.

.

thats what i use...there about 3 or 4 bucks an cone shaped about 2 inches long.. i have mine placed between the 2-3 carb...there a small amout of hose going from the filter to the fuel inlet with..basically the lowest point i can get the filter

without it...it runs the same for a few minutes...then it spits and coughs...guess thats what i get for never re-lining the tank..

but with it i never have found it to run itself out of fuel or anything silly

[chuck hahn]

Or at least unpluig the filter on the down stream side and let it run. Did it run fine in November when you put her away? If os, the you already know the filter wasnt the issue then..but it can be full of coagulated ethanol crap now from sitting.

[mvalenti]

The filter is one of these types..

http://www.ebay.ca/itm/FOR-HARLEY-METRIC-CHROME-GLASS-FUEL-GAS-LINE-FILTER-1-4-/320991847183?pt=Motorcycles_Parts_Accessories&hash=item4abc9ae30f&vxp=mtr&_uhb=1

I took it apart and cleaned it, and yes it was working fine in November. Last time I ran without a filter, I found tons of debris in the bowls after a couple fill ups... one piece of "mung" kept the float needle open... found out the next day.... So I am hesitant to do that.

[Agemax]

The filter is one of these types..

http://www.ebay.ca/itm/FOR-HARLEY-METRIC-CHROME-GLASS-FUEL-GAS-LINE-FILTER-1-4-/320991847183?pt=Motorcycles_Parts_Accessories&hash=item4abc9ae30f&vxp=mtr&_uhb=1

I took it apart and cleaned it, and yes it was working fine in November. Last time I ran without a filter, I found tons of debris in the bowls after a couple fill ups... one piece of "mung" kept the float needle open... found out the next day.... So I am hesitant to do that.

but it will prove if your filter is the problem! if it runs fine without it then go buy a proper one!

[chuck hahn]

Then what your saying is that its time to also clean the tank, pull the petcock to see if the telescopic filter is there..fell off..torn.

If the paint is good then I would sugges doing the Vinegar derusting because vinegar WILL NOT harm the paint.

Then I would do the CASWELL 2 part epoxy tank sealer. Youll never have tank gunk in the system again.

To get the CASWELL tank sealer in without any paint damage, you use duct tape to cover the petcock holes, the sending unit hole ( if applicable) and the filler hole. Then wrap the crap out of the tank with Saran Wrap..several layers thick. Pull the Saran Wrap good and tight as you wrap the tank.

Next, cut a slit in the fiiler neck tape and use a funnel ( I used a cut off pop bottle ) to get the liner into the tank. Retape the hole shut and roll the liner all around the tank for at least 5 minutes and go in all concievable directions and angles. Go slow to allow plenty of time for the stuff to migrate around. Cutting it with shot glass of acetone will make it a little less thick and more managable ( see their instruction sheet ).

[chuck hahn]

Something like this.....

http://www.thegsresources.com/_forum/showthread.php?t=196507&highlight=plastic+wrap

[mvalenti]

Thanks guys, all good info I will post my results as they come. (cold weather)