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Motorcycle Repair/Is my mixture too rich?


QUESTION: I have a '89 Honda NX250. It only has 3200 miles on it. Some days it starts, other days it won't. I recently cleaned the carb spotless. All the jets are unobstructed, the valve and seats are clean with no deposits, the needle has no wear, the float does not leak and float valve seals properly. I noticed that when it won't start the spark plug is wet. I dry it off put it back in and it still won't start. If I let the chamber dry out without the spark plug in and then start it up it runs like it should... for a while. Is my mixture too rich? The spark plug is not fouled but it is a few months old and sooty. The air cleaner is new and has good flow. The float is not adjustable but I do not have the tool to ensure that it is correct. I was thinking that my float is letting in too much fuel into the bowels which would result in too rich fuel, correct? What do you think, should I just replace the float?

ANSWER: Your Floats wont make your carbs run rich.
A dirty air filter can cause a choking effect.
I think the Pilot Jet Screws (Fuel Mixture) Should be adjusted to aquire the perfect fuel mixture.
Check out a (Gunson Colortune Tool) its for setting Fuel Mixtures.
Start with new spark plugs they are cheap.
Also check your choke cable to see it has a little slac and isnt holding the choke partially on.
If the float level is to high the carbs would flood and gas would pour out.
Your running to rich of a fuel mixture and it needs to be adjusted...

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QUESTION: I tuned the pilot screw per the instructions in the service manual and I'm still getting the same problem. Would the colortune tool be worth investing in? Do you have any suggestions about where else my gremlins could be hiding?

The Gunson Colortune Tool is well worth the money.
But first you might try turning the pilot jet screw in 1/4 turn and see how it does.
Some guys turn the pilot in until the engine begins to change, like bog down a bit.
Then they open the screw back up 1/2 turn out.
But to me this is guesswork. the colortune at 2000RPM is the best adjustment I know of.
The jetting of the carburetor may be wrong to.
If the main jet is to large it will run rich also.

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william joseph stack


I specialize in Virago carburetors. Internal parts sizes, Needle and jet sizes for each and every year and model. Hitachi and Mikuni. I also can give tech support and Tech Support for carburetor problems and issues. Carburetor tuning and syncronization. Carbburetor rejetting and dynojet installations for engine modifications. I know every needle and jet size for every Virago made. I have done over50 Virago carb Salesand Rebuilds in 2012. I have over 50 sets ofVirago carbs in stockright now. I Build, Ride and Breath Virago. I have both the 1983 Midnight Virago's. The XV750MK and the XV920MK. 1 of my 1981 XV750H is is Premier Cycles, Billy Joel's Bike Museum.... I am an Honest and Fair man. I am also a Finicky Perfectionist withmy carb work. Ihave all the obsolete hardto find carb parts. I have new diaphragms, new floats, I have the float level setting down to an art. I have fabricated transparent bowls for both version 1 and version 2 carburetors.


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