Subject: Re: Fuel Flow
Author: Jay Williams
Date: Nov 11, 2002, 7:59 AM
Post ID: 1711372569
When I got my '71 Ambo (civilian but with police style tank), it was set up
so that the right petcock fed directly to the right carb and the left
petcock to left carb.
Since there was no reserve with this arrangement, I decided to go back to a
more factory-like set-up. I couldn't procure the correct "X" fitting
locally, so made an equivalent with two "T" fittings spliced together.
On my first attempt, I could get NO fuel to flow through the system, even
though all the hose was new and there were no visible kinks or pinch points.
After much fiddling around and re-routing I was able to get some flow but
not the volume it should have been and it was unreliable at that. Just a
little wiggling or movement of the hoses could cause the flow to slow down
even more, or stop.
After relating my tale of woe to a mechanic friend, he asked where my new
hose was made. I didn't know but on inspection it turned out to be China or
Korea or some such place. He suggested I try it again with USA made hose. I
did, and sure enough, got good flow with the exact same routing. Apparently
the foreign hose lacked the internal stiffness to keep from pinching off the
flow in the bends, even though it appeared un-kinked on the outside.
Don't know what kind of hose you are using, the Asian stuff may be better
now, or there may be different grades of US made hose. So where the hose was
made may not be your problem, but I would bet that somewhere in the system
there are bends that look OK but are actually restricting the flow.
You can always try running lines straight down from one petcock to the
corresponding carb. If you get a good volume of fuel, you'll know it isn't
the tank, petcocks or carbs and that it is indeed the hoses or routing.
Hope that helps,
Jay Williams
| Been thinking about the fuel flow problem I have been experiencing again with Patience. I shortened the length of the top fuel hose on the right side as Andy noticed it was a bit too long and was pinching. After shortening the length and turning on the petcock, no fuel would flow out. If I wiggled the hose, a bit would trickle out but would stop. The fuel lines were full below the splitter, but I would think the fuel would have filled up above it once the fuel was turned on. If I remember correctly, I think the left petcock was opened as well and fuel was in the top of the left line as well. Can an air bubble cause this? Strange thing was my 1st ride on Patience felt as if she was lacking punch, like she was running lean, too much air not enough fuel. When I stopped and put her on the sidestand, I noticed there was no fuel in the right side fuel line going to the carb. When I stood her up, the fuel then went into that right side carb. I don't recall this ever happening before. Patience is at the photographer's shop now, we are taking a family pic with her. I plan to readjust the carbs after the ride home as the idle dropped when she was warmed up after the highway run and pulling the clutch in when stopped dropped the idle down to a stall situation, so I want to up the idle some and make sure the mixture is on. But the fuel flow thing has got we wondering if the carbs aren't set right but the fuel isn't flowing. Andy had the carbs apart and cleaned everything, so those vent holes should be clear. Ideas anyone? Keith Ruff 71 Police Ambassador - NJ |
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