ldnz
12th November 2009, 17:49
Hi all,
Apologies for the long post, but I want to be thorough because this a pretty confusing problem!
Background:
I was riding across the bridge the other night when bike felt like it was running out of fuel, ie slightly hesitant/surging. Switched to reserve and all went well again for a k or so before it started doing it again. Limped into the caltex on fanshawe with the bike running really roughly and wanting to stall, filled it right up (it took right on 15 litres, reserve level) and on starting experienced the same problem. It was idling very badly, very hard to take off without stalling, and if you applied reasonable throttle it would run like shit through til about 10000 rpm where suddenly it became full powered and pulled a wheelie.
Limped it back out west and tore it apart. All plugs were wet and on starting fuel was observed pouring down all 4 carbs ie visible pooling on the butterflies. It was possible to get the bike running but its incredibly rich and keeps wanting to stall out. The fuel pump is running non stop and for some reason none of the float valves are closing.
Checked fuel pump pressure, its at 3.5-4psi where manual suggests 1.5-2.3psi. Ok so thats high, could have damaged something. Took one of the float bowls off. Careful inspection shows that the valve and valve seat are in immaculate condition and with only the lightest pressure on the float the valve closes sufficient to stop the fuel entering bowl. Took fuel pump out of the circuit and went to gravity feed straight from the tank, same symptoms observed.
Interestingly (and confuzzlingly!) when one of the bowls is off and the floats are held up on that carb with my finger, NONE of the carbs flood. I cannot understand why this is.
Anybody got a bucket of clues to shed some light on this? I am so confused and what was looking like a simple problem just isn't. I must be missing something simple.
Cheers for making it to the end of this!
Ben
Apologies for the long post, but I want to be thorough because this a pretty confusing problem!
Background:
I was riding across the bridge the other night when bike felt like it was running out of fuel, ie slightly hesitant/surging. Switched to reserve and all went well again for a k or so before it started doing it again. Limped into the caltex on fanshawe with the bike running really roughly and wanting to stall, filled it right up (it took right on 15 litres, reserve level) and on starting experienced the same problem. It was idling very badly, very hard to take off without stalling, and if you applied reasonable throttle it would run like shit through til about 10000 rpm where suddenly it became full powered and pulled a wheelie.
Limped it back out west and tore it apart. All plugs were wet and on starting fuel was observed pouring down all 4 carbs ie visible pooling on the butterflies. It was possible to get the bike running but its incredibly rich and keeps wanting to stall out. The fuel pump is running non stop and for some reason none of the float valves are closing.
Checked fuel pump pressure, its at 3.5-4psi where manual suggests 1.5-2.3psi. Ok so thats high, could have damaged something. Took one of the float bowls off. Careful inspection shows that the valve and valve seat are in immaculate condition and with only the lightest pressure on the float the valve closes sufficient to stop the fuel entering bowl. Took fuel pump out of the circuit and went to gravity feed straight from the tank, same symptoms observed.
Interestingly (and confuzzlingly!) when one of the bowls is off and the floats are held up on that carb with my finger, NONE of the carbs flood. I cannot understand why this is.
Anybody got a bucket of clues to shed some light on this? I am so confused and what was looking like a simple problem just isn't. I must be missing something simple.
Cheers for making it to the end of this!
Ben