Hello,


I have a 2007 Suzuki eiger which I purchased when new. It has about 2,000 miles on it. It has always been cold natured which I understand is due to the factory settings being lean. I do not take issue with that.


My problem is this. Last year I was riding it down the road and it started running bad, cutting out etc like it was running low on fuel. I switched it to auxiliary fuel and it made no difference on its performance.


I pulled the carb and the fuel tank off. I cleaned the tank, fuel valve screen and rebuilt the carb with a factor spec kit. It ran better for sure but not as it should. It would puff some black smoke when you got on the throttle. It would idle at first but over the last few months that did not last. Now, When I pull off the suction hose going to the fuel valve it would idle smooth as can be. I pulled the carb on two separate occasions after, cleaned, and made sure the float was set to factory spec of 17mm. I replaced the oil filter and put in new oil. I also pulled the tank off a couple more times, cleaned it, cleaned the valve screen and put in new gas.


I ordered a new factory spec carb kit. I rebuilt the carb yesterday. Yes, I cleaned it thoroughly and I'm not new to carb rebuilding. I replaced every single part provided in the kit. I checked and made sure the float was set at 17mm. I followed the instructions in my Suzuki shop manual which I purchased.....


I have a fuel filter between the fuel valve and the carb. Fuel flows well from the valve when engine is being cranked and stops when it is not being cranked other than a drip every 5-10 seconds maybe longer. It appears to be operating as designed for the most part. I also put a fuel filter on the vent hose running from the carb to up under the seat.


Now, after a fresh carb rebuild the atv still will not idle unless I take the suction line off the fuel valve. I put it on the road and ran it ride open at 55mph and it never missed a beat. It still puffs the black smoke when you hit the throttle. I replaced the spark plug after the last rebuild and set the gap to spec. I'm fixing to go buy a new NGK CR6E to put in it this evening. I put a spark tester on it and the spark is constant to the spark plug so I do not feel it is an issue with the magnets on the magneto/flywheel.


I understand it's getting to much fuel or maybe not hot enough spark to burn said fuel but I can not figure out the cause. Any help would be much appreciated as I can not afford to take to the dealer for repair......

 

I'm thinking that if your bike has a diaphragm fuel pump, that the pump is leaking a tiny bit of fuel into the vacuum port of your carb or intake. The signal ( pulse ) for the pump....do you know what I'm talking about?

 

Yes, I believe I do. This diaphragm is the one on top of the carb or the diaphragm on the side of carb? Before I rebuilt the carb this last time (yesterday) I had noticed that the vacuum line running from the carb to the fuel valve was full of fuel. I did pull the vacuum line off yesterday to see if it would idle with out it attached to the fuel valve and I did not notice any fuel in the line. I am going to put this new (hotter) plug in it when I get home and ride it around a good while. Then I will check that vacuum line for the presence of fuel.

 

ctx, the fuel pump will not be attached to the carb.. ( I'm not sure your bike even has one ), it will be part of the petcock/fuel valve or located on the left side of the ATV somewhere towards the front. Trace the fuel line from your carb...see where it attaches to. And sometimes the petcock/fuel valve is also a fuel pump.....this is seen alot on Suzukis.

 

Ok, a vacuum line runs from the carb to the fuel line which opens the fuel valve and allows fuel to run directly from the valve to the carb

 

Check that vacuum line....should be no fuel in it...shouldn't even smell like fuel. If it does, the the vacuum line may be pulling fuel into the carb, which means the fuel pump diaphragm has a small hole in it. If the vacuum line has zero fuel coming out of it ( shake it, see if a drip or two comes out of it ), then your problem will still be in the carb.

 

Pulled vacuum line soon as i got home after work and it was plum full of gas. Put new plug in and still runs like junk except when wide open. Idles great when vacuum line is unhooked until it runs out of gas....

 

You have found the problem.....

 

But what is the solution? Do i need a new fuel valve or??? Nothing drips out of the fuel valve when the vacuum line is off. Hows is the vacuum line filling with fuel ?

 

As mentioned in an earlier reponse, the fuel pump diaphragm has a hole in it, allowing fuel to be sucked into the vacuum line. Solution is to replace the fuel pump.....