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Discussion Starter · #1 ·
I've been trying to tune the carbs on my 2004 Legend 380 fan with no luck. I can't get rid of that low end bog. It won't let me rev the engine beyond idle with snapping the choke lever. I've cleaned the carbs, new boots, plugs and oil. My Pilot air screw is about 1 1/2 turns out. Primary slide height was set with the 0.067 drill bit and it idles great now. Just doesn't have a snappy response between idle and part throtle. The motor only has 1300 km on it. Thanks for any tips
 

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Plugged pilot jet or pilot circuit
 

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Discussion Starter · #3 ·
I took the pilot needles out and made sure they were clean. Carbs have been taken apart and cleaned many times now. I set the slide height on the motor side with the drill bit 0.067" then the pilot air screw was turned out 1 1/2 turns. It idles real nice but there just isn't any 'crispness' to the throttle. Bogs right down unless you give it choke then revs right up. Stumped.
 

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Carb boots good how about a cracked y-pipe lean is what causes a bog so maybe the fuel is fine but too much air for the available fuel

Sent from my iPad using Tapatalk
 

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Did you check your fuel inlet needles/seats when you were in the carbs? I had a similar bogging problem a couple of years ago. The carbs were spotless but the fuel inlet needles had a little crud on the sides and they were sticking. Maybe yours are stuck partially closed and you're not getting enough fuel when you crack the throttle?
 

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If you need to use the choke then it's a fuel issue.Could be from a air leak, clogged jet, or fuel delivery issue.

I was having a similar issue last year. Needed to use primer to bring hanging idle down, bogging. All pointed to a fuel issue. I dont know how may times I cleaned the carbs, checked seals, boots. I finally gave up and parked it in the corner. Last week I pulled every part of the fuel system. Finally found the problem-
http://www.dootalk.com/forums/topic/526591-fuel-pump/
 

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I took the pilot needles out and made sure they were clean.
Pilot jets dont have needles. Just sayin'.

IF everything is clean then you need to richen up. Bigger pilots, raise needle, whatever.
 

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As mentioned stuck needle and seat had same issue before.

To the comment above lean isnt the only thing that causes a bog on bottom end you can also have a rich fuel bog. To big of a pilot causes fuel bog usually or incorrect slide adjust stuck choke but not in this case it appears.

A fuel bog is usually right of the hop when u crack the throttle burbbly then go, a lean is go die go.

But in this case having to use the choke hints at a lean condition. .

Could be a plugged fuel pump plugged tank filter etc.

Hard to tell over the internet.

Does sled run fine after u flip choke and get into different range of the carb I.E main jet are

Michael M
 

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Discussion Starter · #11 ·
Ya it runs great after about 1/4 throttle with the choke. After I turn off the choke it revs right up. I've taken the slides off and raised and lowered the clip and no change. The fuel pump and plugs are new. I will also remove the gas tank and change out that filter.
 

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Not being a jerk but do you have less than an inch of gas in the tank ? Is the air box clear of mouse nest ? Batards find there way into everything. Is it one cylinder or both, meaning is one plug wet n other dry ? Could the choke be stuck/ sticking ?
 

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Check the choke , also the choke cable for binding somewhere.
 

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Pilots don't look anything like a needle. You need a small shirt pocket size screw driver to take them out. Alot of people miss them, just willing to put my bet down it is the pilots are plugged. Just go buy some new ones and have your dealer show you where they are in your 380 carbs...............good luck
 

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did you run a small wire through the pilot jets? turn the air screws in a 1/4 turn and see if it clears up the bog. also check the crank seals or do a leak down test to rule out a vaccum leak.
 

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Discussion Starter · #17 ·
No back fires. no cracks in y pipe. Original pilots and have been removed and cleaned including with wire. The only thing replaced in the carbs was the fuel inlet needle and seats. They didn't have my size of 1.8 so sold me 2.0 saying no real difference. Can i check for air leaks using propane like you would on a car engine? thanks for all the tips
 

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No back fires. no cracks in y pipe. Original pilots and have been removed and cleaned including with wire. The only thing replaced in the carbs was the fuel inlet needle and seats. They didn't have my size of 1.8 so sold me 2.0 saying no real difference. Can i check for air leaks using propane like you would on a car engine? thanks for all the tips
Are you sure the 2.0s didnt change the float level?
 
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