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2006 Virago 250
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Discussion Starter · #1 ·
I have a 2006 Yamaha XV250 (single carburetor) with 10,000 miles on it.

It came with a carburetor that was running super rich. I replaced it with a chinese replica that I'm slightly suspicious of (different story), and I'm trying to get the OEM carburetor working.

It runs best with the fuel screw turned all the way in, but it's still making the plugs black.



I thought it was probably the choke, since the original choke and cable were sticking. But it's still rich with a new choke (which was working fine on the replica carburetor). The same choke worked fine on the replica, and everything looked clean in there.

I tried swapping the pilot jet from the replica, it ran even richer.

I tried swapping fuel screws, no change.

The main jet/tube worked fine on the replica carburetor, so I'm not suspicious of those.

The float level was high. I reset it to spec and it's a bit better, but still rich with the fuel screw all the way in

I'm using the bowl cover from the replica with its accelerator pump, since the oem was sticky.

The jet needle looks non-oem, like one from a rebuild kit. From what I understand, it shouldn't do much when idling, but I haven't ruled it out yet.

I believe it's running rich past closed throttle, since the performance seems worse compared to the replica. I'm not entirely sure though.

Any ideas?
 

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Save them all!
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4,278 Posts
Well, verify your float needle is in good shape - if it's ringed or worn that will cause it to run rich. You already took care of the float adjustment, but double check that's within spec. Also make sure the float isn't sunk (no fluid inside if that's possible on yours.)

How's the air cleaner? A plugged or oil soaked air cleaner will cause a bike to run rich.
 

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Ace Tuner
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3,522 Posts
First, I'd get rid of ALL the Chinese parts.

Sounds like the original carburetor needs a good cleaning.
With all of the jets removed, make sure you get all of the passages (ports) inside the carb body itself clean and clear.
 

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2006 Virago 250
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10 Posts
Discussion Starter · #4 ·
The air filter has been ruled out (replaced it when I got the bike, and the other carburetor doesn't run rich).

The floats were set based on the fuel level, so it's not a leaking valve.

Any idea what I should be focused on cleaning specifically?
 

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I have a 2006 Yamaha XV250 (single carburetor) with 10,000 miles on it.



It came with a carburetor that was running super rich. I replaced it with a chinese replica that I'm slightly suspicious of (different story), and I'm trying to get the OEM carburetor working.



It runs best with the fuel screw turned all the way in, but it's still making the plugs black.







I thought it was probably the choke, since the original choke and cable were sticking. But it's still rich with a new choke (which was working fine on the replica carburetor). The same choke worked fine on the replica, and everything looked clean in there.



I tried swapping the pilot jet from the replica, it ran even richer.



I tried swapping fuel screws, no change.



The main jet/tube worked fine on the replica carburetor, so I'm not suspicious of those.



The float level was high. I reset it to spec and it's a bit better, but still rich with the fuel screw all the way in



I'm using the bowl cover from the replica with its accelerator pump, since the oem was sticky.



The jet needle looks non-oem, like one from a rebuild kit. From what I understand, it shouldn't do much when idling, but I haven't ruled it out yet.



I believe it's running rich past closed throttle, since the performance seems worse compared to the replica. I'm not entirely sure though.



Any ideas?


I am not carburettors expert or specialists
as per my DIY experience of last 45 years
suggest to replace spark plugs to original
specifications by referring owners manual

Cold spark plugs can become black with good
carburettor & proper settings



Sent from my iPad using Tapatalk
 
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