Motorcycle Forum / General / Yamaha / May 2007

The indication is that the idle mixture is too rich, causing the idle RPM to
be too high when the engine gets hot.

This might be caused by improper adjustment of one or both of the idle
mixture screws ( item # 5)

http://www.bikebandit.com/partsbandit/showschematic.asp?dept_id=2131417

But the idle mixture screws are hidden behind the EPA anti-tamper plug and
you would have to drill the plug out to adjust the idle mixture screws.

If you could get the mechanic at your dealership to sniff the tailpipe with
his exhaust gas analyzer, he could tell you for sure whether the mixture was
too rich without drilling out the EPA plugs.

When the idle mixture screws are set too rich, an inexperienced mechanic
compensates for slow idle RPM by turning up the master idle knob.

This uncovers a pattern of three transition holes and the engine sucks excess
gasoline through the transition ports, which are not controlled by the idle
mixture screws at all.

Another possibility is that one of the choke valves is not closing fully,
even though the lever or knob position appears to indicate that the choke is
not ON.

You could verify that the choke valve is leaking by putting your finger over
the bypass intake hole on the right hand side of each carb, but you would
probably have to take the gas tank off to do that.

Another possibility is that one of the float valves is sticking open, raising
the fuel level enough to make it easier for the idle jet to suck up excess
gasoline.

Or the floats might just be set too high. There is a procedure for checking
the fuel level in comparision to a line cast into the bottom of the float
bowl of semi-downdraft carbs by using a length of clear plastic tubing
attached to a spigot coming from the float bowl.

I can't tell if your carbs have the line, the fuel shut off solenoid is right
there on the float bowl.

Of course there is always the possibility that your throttle cable might not
have the required minimum amount of slack.

On May 24, 9:34 pm, "farm282...@yahoo.com" <farm282...@yahoo.com>
wrote:

Albrecht

Hello, and thanks for your reply. I have heard that the "Pilot Jet"
causes this error also is that the same one that your talking about?

On May 24, 9:34 pm, "farm282...@yahoo.com" <farm282...@yahoo.com>
wrote:

Thanks Albrecht , I cleaned the carbs and she runs fine