Odd problem, cant quite fix it (fixed)

Replaced the fuel line, added an inline filter, and an inline petcock, plugged the vacuum to the tank petcock and leave the tank pc in "prime" position. (its been rebuilt, and leaks..sometimes..or not..or does...so I dont trust it.)

First night out, got 60 miles out on some two lane and it started to die- sputtered to the side of the road, quickly figured out I had the line too short, whole area under tank got hot, rubber hose got warm, folded on itself fuel starve.
Next day re-routed fuel line, made it longer. Ran about 95 miles no problems, ran great.
Few dozen short trips no problems.
Just now was about 35 miles from home, same thing happened, coasted to side of road, waited 3-4 minutes and made it 3/4 of the way home happened again, another 2-3 minutes wait, and off we go.
Looked at the fuel lines-no kinks, high areas, see thru filter is half full of gas. No leaks- but sometimes there is a slight gas smell around the carbs, but they are dry everywhere I can see. Almost more like the smell of gas and an engine that is burning oil, but faint.

thought it might be electrical- you know, after an hour something gets hot and fails, have had things like that happen in the past, but never a start 3-4 minutes later and ran fine.
Sure think its a fuel starve..somehow...but am totally open to suggestions.
thanks

hook a vacuam line back up to stock petcock

Have you checked the tank vent in the cap?
Also disconnect fuel line and check flow into a container.

wireman wrote: hook a vacuam line back up to stock petcock

I leave that one on "prime" its my understanding if its like hondas, yammers etc prime is wide open no?
I'd say that was it except putting on so many miles. I usually kill the petcocks a few blocks from home and sometimes thats all it takes to start puking out

Motor Head wrote: Have you checked the tank vent in the cap?
Also disconnect fuel line and check flow into a container.

LOTS of flow, I'll check the vent in the cap in the AM.

is it possible that somehow the screen in the line into the carb is partially plugged?
thinking outloud, I dont think so, as this usually happens going steady around 3000rpm vs. 4k and up, maybe the vent cap just starting to plug, and yanking the throttle is enough to get it open...

thanks wireman, motorhead, good stuff- any other ideas I'm open

Would test run with fuel tank cap ajar (partially open and not snapped down) to determine whether fuel starvation is resulting from insufficient fuel tank venting.

Good Fortune!

What In-line are you using? One for a Gravity system? those car filters are for like 4-6 psi flowing through them. They can restrict the flow on a bike.

This free-flowing in-line filter usually works well in KZs.

www.z1enterprises.com/Fuel-Filter--High-...ne-clear-14-293.aspx



Good Fortune!

sorta looks like that ^ but paper element.
Good point, if its designed for pressure, even 3 pounds, that 2500-3K lurching along in high gear could be just enough.
I'll check the flow with the lid on and some hand pressure to speed things up.
also, seems to happen more with nearly an empty tank...and that would lend credence to the inline filter, more gas, more weight pressing down..hmmm, Im thinking its the filter..

Yep, low fuel level = less Head Pressure. Change the filter out.

Ah nothing like gearhead think tank.:laugh:
thanks

I'll do that and post a follow up for anyone searching in the future.

Medina wrote: ...seems to happen more with nearly an empty tank...and that would lend credence to the inline filter, more gas, more weight pressing down..hmmm, Im thinking its the filter..

Imo, points more suspicion to tank vent issue -- not a matter of gasoline volume inside the tank.

Gasoline flows from the tank at the same rate regardless of whether the tank is full or almost empty.

Good Fortune!

Patton wrote:

Medina wrote: ...seems to happen more with nearly an empty tank...and that would lend credence to the inline filter, more gas, more weight pressing down..hmmm, Im thinking its the filter..

Imo, points more suspicion to tank vent issue -- not a matter of gasoline volume inside the tank.

Gasoline flows from the tank at the same rate regardless of whether the tank is full or almost empty.

Good Fortune!

I might be remembering incorrectly, but a full gas tank exerts more pressure on say a 5/16" hole than an empty one as the volume of fuel sitting on top of that hole is greater-more mass pressing down than a nearly empty tank. ...I think...lol, I'm getting used to being wrong however