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Discussion Starter · #1 ·
On my way home from work yesterday I started for run out of gas and switched to reserve. I went about another mile and I ran out of gas so it seemed. I leaned my bike over in its side to get any gas I had over to the petcock. It started ran for a short time and died. I had to do this two more times to get to a gas station. It wasn’t running very well it was only running on one cylinder. When I filled up it only took 2.5 gals to fill. I had a ½ gallon left in my tank. My tank holds 3.2 gals when full. Any thoughts on what’s going on? I should have pulled the gas line off to see if I had a good fuel flow before I filled up but it wasn’t possible. As soon as I filled up it ran fine again. I pulled the petcock out about a week ago and tested it on main and reserve and it worked as it should. I’m using a K&N 90 degree fuel filter installed by the carbs with a short line coming off the carbs and a longer fuel line to the tank. The only recent changes I switched to a different set of carbs that I cleaned up using Larry’s book. I also moved the fuel filter back down by the carbs. Before the filter was on the side of the carbs just on the outside of the frame. I’m at a loss. I think I should replace my petcock and move on. I’m just wondering if anyone else has had this problem. The only other change I converted my vacuum petcok to a standard.
 

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I'm not sure what is happening either. Maybe a loop in the fuel line from the petcock to the filter? That can sometimes cause issues. I thought all the Customs had a 2.9 gallon tank, but you still should have had close to a half gallon left when you filled up.



Probably the easiest way to check would be to either attach a nipple and hose to where the line enters the carbs and see if you get good flow. Try to keep the same relationship as it is now to the carbs. Or you may be able to just open the drains and put a container under the drain hoses. See if you are getting a good flow for several minutes. Then dump the gas in your lawn mower.



I doubt that changing the petcock will help, they usually either work or not, working part-time would be unusual.
 

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Hmmm not sure

sounds like a restriction of some kind doesnt it?

I do remember wouter having problems which he eventually realised

were due to having too much fuel hose and it was kinking and

restricting the flow by closing off the inner passage of the pipe



Also is it possible the filter has picked up debris during recent work

thats restricting flow?
 

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Discussion Starter · #4 ·
I was thinking a restriction also. WIth a full tank of fuel I wonder if there is enough weight, prerssure etc... to have a good flow of fuel and when it gets down to 1/2 gal not so??? I think I'm going to switch out the fuel filter and see what happens. Any suggestions on a different filter?
 

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Could it be vapor locked? Did you hear a hiss when you opend your tank?



Not sure if that is common on these but it can cause that issue. Next time it happens try and open your cap, let some air in and see if it will run.
 

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82 model tanks had 3.2 gallons.



Seems like there has to be a restriction. It could be several things. If you used a replacement oring for the petcock it could be squashing down to far and blocking the hole that feeds the gas. There could be dirt in the petcock or a few different items.
 

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How about debris in the tank? With less fuel in the tank, any suspended sediment will be more dense, and would possibly clog the screen more easily.



Did you check the screen when you had the petcock out? Try dipping a magnetic parts grabber down to the bottom of the tank. It will pick up rust scale if there's any in there.



R
 

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Discussion Starter · #8 ·
I had some rust in my tank last summer and I cleaned it out with Muriatic acid. I’ll check to see if there is any debris in the tank. When I pulled my petcock out last week I also pulled the screen and it was clean. I think I’m going to try back flushing my petcock and see if any thing comes out. I think it’s a restriction I’ll just have to chase it down. I don't think its an issue with the cap. No hissing when I took the cap off. I'll check just to make sure.
 

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I'd have the petcock off and give it check and blow through.Some more debris may have clogged up the reserve ring at the bottom.I have a crappy repaired tank on my Bitsa CX and it's still giving some crud even after mega cleaning and repair.As I always use in-line filters it's no biggy,just a PITA for a while.
 

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When you cleaned the tank last year with acid did you line the tank. If not you're going to get rust in the tank quick.
 

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I said the same thing about one of my tanks. You should have saw it after 6 months. Pretty much stopped me dead.
 

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Discussion Starter · #13 ·
I replaced my filter tonight. I noticed that my old one was getting pinched by the clamps on the hose. I'll see if it make a difference. I had a good flow of fuel from my petcock in run and reserve positions.
 

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Could it be vapor locked? Did you hear a hiss when you opend your tank?



Not sure if that is common on these but it can cause that issue. Next time it happens try and open your cap, let some air in and see if it will run.
I agree. A blocked fuel cap breather can cause these symptoms.
 
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