St1100 too rich, stalls
- Thread starter Miskusz
- Start date
Smudgemo
Intermodal Man of Mystery
This is a rich condition, right? I was thinking maybe check the rubber tips of the float needles if you have the carbs apart, but it seems unlikely they'd all be bad. Or enough of them to cause issue, but maybe. At least worth looking now that you have access. Make sure their clips are oriented like Adam shows.
Just out of curiosity, did you ever try to disconnect power to the fuel pump? If the bowls have fuel, the bike should run for a bit before running out of fuel. Alternatively, you could employ a remote fuel bottle using gravity rather than pressure. What if the pump is moving too much even with the bypass? Is that possible? I don't know but it's just a thought that crossed my mind since you have an aftermarket pump.
Just out of curiosity, did you ever try to disconnect power to the fuel pump? If the bowls have fuel, the bike should run for a bit before running out of fuel. Alternatively, you could employ a remote fuel bottle using gravity rather than pressure. What if the pump is moving too much even with the bypass? Is that possible? I don't know but it's just a thought that crossed my mind since you have an aftermarket pump.
Slydynbye
Will ride for Pie
I always wondered if it made a difference......I tried both ways and couldn't SEE the difference.
Smudgemo
Intermodal Man of Mystery
I don't disagree. I could see how it would be more possible to slip off the tab in the "wrong" orientation, but how possible? Got me, but I don't want to go back in that far if I don't need to..
Hello all!
So current status report: Adam the carb master contacted me, we are in deep diagnostics. I removed the carbs, pull apart (again) to all small components, assemble it.
Things i found:
- there was no washer under the needle seat ( i did not even realized at first). When i blew into the fuel line, small bubbles come out. So new seats (just in case) with new washers.
-i have never seen during my short life something like this. The fuel mixture screws do not fit to all holes. In one hole one was fully seated another one extended about 2 mm-s. Super aftermarket thingy..
After these two, i checked it: it's starts good, no stalling, but still rich (when rev go under idle, exhaust gases burning my eyes)
- While measuring fuel pressure (aftermarket airtex pump with oem pressure regulator), i accidently knocked over the spark cap of cylinder 3, which came of partially. To my surprise it's not really affected the bike. So i started to pull around, all 3 others had significant down effect. So i pulled the caps and measured with multimeter. Between 2 and 4 cyl. 25k ohm, between 1 and 3 cyl Infinity. I pulled the carbs removed the plug cables, number 1 is ok (5k), number 3 is infinity. But the strangest thing, i have spark in It. But looks like the bike is running with 3 cylinder.
So current status report: Adam the carb master contacted me, we are in deep diagnostics. I removed the carbs, pull apart (again) to all small components, assemble it.
Things i found:
- there was no washer under the needle seat ( i did not even realized at first). When i blew into the fuel line, small bubbles come out. So new seats (just in case) with new washers.
-i have never seen during my short life something like this. The fuel mixture screws do not fit to all holes. In one hole one was fully seated another one extended about 2 mm-s. Super aftermarket thingy..
After these two, i checked it: it's starts good, no stalling, but still rich (when rev go under idle, exhaust gases burning my eyes)
- While measuring fuel pressure (aftermarket airtex pump with oem pressure regulator), i accidently knocked over the spark cap of cylinder 3, which came of partially. To my surprise it's not really affected the bike. So i started to pull around, all 3 others had significant down effect. So i pulled the caps and measured with multimeter. Between 2 and 4 cyl. 25k ohm, between 1 and 3 cyl Infinity. I pulled the carbs removed the plug cables, number 1 is ok (5k), number 3 is infinity. But the strangest thing, i have spark in It. But looks like the bike is running with 3 cylinder.
Where are you measuring between? - The plug caps can be disassembled with a large flat bladed screwdriver. Inside is the clip that latches on the spark plug, a resistor that should measure 5k ohms and a spring. On mine, there was some corrosion where the spring pushed against the head end of the cap. I cleaned everything up and ran some co-ax wire sleeve across the spring. Does anyone know the function of that spring, other than maintaining a mechanical/electrical connection?
Hello Roger,
I disassembled the cap, the resistor itself is 5k, the spring and connector ok, the cap itself is bad (without the cable) is infinity ohm.
I measured the same for cyl. 1 cap, it's ok. So my thinking probably broken a little inside, where no conductivity can be measured, but the high voltage can arc it, weakening the spark's arc.
And this weakened spark under the cylinder's compression is unable to ignite it (?)
I disassembled the cap, the resistor itself is 5k, the spring and connector ok, the cap itself is bad (without the cable) is infinity ohm.
I measured the same for cyl. 1 cap, it's ok. So my thinking probably broken a little inside, where no conductivity can be measured, but the high voltage can arc it, weakening the spark's arc.
And this weakened spark under the cylinder's compression is unable to ignite it (?)
A trick with a wet or dirty tractor engine was to add a small gap in the HT lead (across a button!) that would get the HT voltage high enough to spark before the voltage leaked away at the plug. Not that it's much help to you! .....Sorry - I had something similar once - looks like you need a new cap...
.....Sorry - I had something similar once - looks like you need a new cap...