LegendsRacer - Legends & Bandolero Racing Forum
LEGENDS => Engine Care & Tuning => Topic started by: JGRacing on February 23, 2009, 01:05:58 pm
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The only experience I have with these carbs is putting in a jet kit last year, so I need some help. I am using the set for the first time and am running in the rebuilt motor. When I am idling everything is good, but once I get up to operating temperature and hit the throttle, the number 2 carb starts coughing raw gas out around the needle where it passes through the bore, out the air jets, and out the vent hose that comes out between the 1 and 2 carbs. I think a float might be sticking, but not sure why it would not happen as soon as I fire up the motor. When I go back to idle, it still keeps coughing out fuel. Before I dig into this, does anyone have any advice on what I should be looking for?
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Could be several things:
1. Trash in needle & seat area -- remove needle & seat, clean, blow w/ air & replace; may also be worn and need a new needle & seat;
2. Improper float height -- reset per manual ( I can't remember off top of my head here at the office)
3. "Wet" float -- As floats get older or develop hairline cracks, they absorb or hold fuel inside, making the float heavy, therefore it won't rise properly and seat the needle, thus fuel continues to come into the bowl.
4. Testing: remove carbs & drain fuel. turn carbs upside down and put hose onto fuel inlet. Gently blow thru hose, it all needles are seating properly, you should not be able to pass air thru the hose, unless you blow on it substantially. If air is passing, gently hold the floats for #1, # 3 & #4 down with your fingers and test only the "trouble" float. If it still passes air when you push down on #2 float, then the needle is not seating. If air does not pass, the needle is seating, and the problem is likely the float is "wet" or improperly set.
I'm sure there are other and better ways, but this is how I do it. Hope it helps.
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Thanks. I will give it a try this week.
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in my experience 9 times out of 10 it is the float is not set properly. take a very small flat screwdriver and flex the little tab that shuts of the float sooner.
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I set the float level according to the Yamaha book and the instructions from Redline, but first time with these carbs so it is entirely possible that I got one wrong. I was thinking float, but does it make sense that this does not become a problem until the motor if warmed up?
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I finally got a chance to pull the carb apart, sprayed it out with carb cleaner, checked the screen, put it back together, and it works. Not sure if something was just a little gummed up or what was wrong with it.
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Thanks for the update!
Steve