Petcock filter direction

[CaptonZap]

So I was thinking about this today and have another question.

When you put your reserve on, does your bike run good until it is out of gas?

Mine runs ok for a few miles and then starts the bucking.

Last weekend I put mine on reserve at 155 miles, not because it was bucking, but because I knew it was mileage time to be thinking about it. Then at 165 miles I was a mile away from the gas station when it started to buck. I was surprised at only 3.8 gal. to fill up.

Makes me remember last year when it was "low" on gas and died on me and I had to walk three miles home. Looking in the tank it sloshed gas so I wasn't truely empty. I Thought I had a real problem. Once I trailered it back home and checked may things did I put gas in it and it cranked up. So course by that time I had fiddled with several things and wondered if it was just out of gas. But when you put a gallon or two from the mower and then fill up at the station, you can't really know how much went in.

Take your petcocks out and look at the screens. If the bottom portion of the screens are discolored, and covered with some residual alcohol crud, that could impede the flow when in reserve position. Some acetone and a toothbrush should remove the crud, just be gentle with the screens.

CZ

[DiverRay]

Also, check the back of the petcocks and verify the vent for the vacuum system is open. this COULD cause problems in both directions, not opening or closing properly.

[Bartman]

I got home from work today and rolled the bike outside and put on the center stand. Then I put empty five gallon gas cans on both sides. Put two gas lines from the petcocks into the cans. Then opened both to prime. Watched until the left side stopped flowing (10~15 minutes). I was expecting the right side to flow for several more minutes thinking another gallon to come out. But it flowed for about 45 more seconds and then stopped.
So now I wonder if it needs that gallon as head pressure and that is why it bucks at around 4 gallons are used up?

[DiverRay]

Try what CaptonZap said to do. Pull both petcocks and clean the screens with a tooth brush and seafoam or barrymans'. It sounds as if the screen is causing the problem, and when you get close to the bottom of the tank, no pressure, no flow.

[MPittma100]

Petcocks

The petcock base where the filter mates to it has two holes in it. One or both of these holes can get trash in them and partially or fully block the flow. This is especially possible if the filters have any tears in them. Check these holes and clean them out. Also make sure that the filter mesh is intact.

If you have had the petcocks apart, you may have noticed that the locating pins for the filters in the petcocks are in opposite locations. I may be wrong, but it could be possible to put the petcock bodies on the wrong sides causing the filters to be backwards?

[Bartman]

OK, there are two problems.

One is that I put the petcock handle pointing backward over the reserve word....thinking that I am on reserve. BUT NO, I am really pulling gas from the prime port. That shouldn't be a problem since that port has filter all the way down to the petcock, but I must still have a needle and seat leaking problem????

Second problem is that the gas filters that are in the tank have a 67mm tall column tube. I pulled my old broken filters out of the scrap box and they are only 50mm tall. That 17mm must equal a good portion of gas!

[Bartman]

Here is a picture of different gas filters.

http://i1339.photobucket.com/albums/o716/bartjackson1/image.jpg2_zpsh5tygmax.jpg

[jetmechmarty]

Different fuel tanks have different petcocks. That tower is often the only difference.