help, venturi needle bouncing
Hey guys, Im new to here, but need some help
I just bought a 2000 kawasaki vulcan 750, 11000 miles on it, garage kept.
Been battling a running rich problem.
I have had the carbs apart 3 times and kept thinking i had a jet stopped up or float level problems. I was running way rich on front and back cylinder, way way rich. I got inside the carbs the third time to find that my rear carb float needle seat, was pressed in incorrectly by either keihin or previous owner. I had to re clock it so that the holes were lined up so that fuel could come through them. Before the fuel was being forced up by the needle and preventing the needle to close. I also found that my rear carb air fuel screw was broken, fished out the tiny broken part and replaced
Now i have the air fuel screws set at 1 1/2 turns and I am still a little too rich on the front cylinder.
I also noticed that the venturi needle on the front carb is boucing top to bottom at a rate of about one bounce a second
While assembling i made sure all passages were unclogged and the vaccuum diaphrams had no holes and were properly seated
Now the rear cylinder has cleaned up, no more rich and the front is still puffing black fuel smoke. all of this is taking place at idle to 2500 rpms. then clears up past that.
mods it has is cobra unbaffled exhaust. i have good fire on all plugs, good compression, clean uncontaminated fuel, petcock is operating good.
Cant figure out why the venturi needle is boucing. Do i have so much carbon buildup on the intake valves that it is sucking for a second, is there a leak between the head and carb creating a sucking effect, is it possibly out of time.
any help would be greatly appreciated. I spent 6 years in NASCAR, and 1 1/2 years in nhra as a builder, thought i knew carbs very well, but i am overlooking something that is probably very obviouls, help please