84 VF700c Magna Carb problem

[iepxs]

I bought a 84 VF700c Magna from a guy who let it sit (without proper prep) in his garage for 12 years. After going through and changing plugs, *all* fluids and battery I cleaned out the carbs, put them back in and the bike ran like new...for about 200 miles. Then, while on the highway one afternoon the bike started to bog and the throttle got sticky. It will idle (barely) but boggs when given gas. I took the carbs back off and there is a sticky dark brown residue through most of the middle of the carb and throttle plates. I'm guessing the bogging was a result of this stuff gumming up the carbs and I'm in the process of re-cleaning the carbs, but would like to know if anyone might have an idea of what caused this. I'm worried that just cleaning out the carbs will only temporarily fix the problem. Also note - I did install a new fuel filter before all this happened. I have not had the gas tank(s) cleaned. Ideas? I've posted a picture of one of the 'gummed up' carb throttle plates here: http://www.dontcamerame.com/Gallery2/ma ... emId=19495

[Hatch]

I would guess that the tank has some nasty "crud" in it. Can you see in the tank with a flashlight? And if that is the source of the problem might as well replace the fuel lines and clean the petcock.

[MuayThaiRider]

I would also add an inline fuel filter. You can get them on BikeBandit.co for $3. I have them on everything I own. They keep the diry and junk out... Cheap fix.

[flynrider]

Yep. My guess is that you re-contaminated the fuel system with gunk from the tank. If it sat for 12 yrs. with old gas, there's probably a lot of decomposed deposits in there. I second the fuel filter recommendation and also suggest that you pull off the petcock and check the screen.

[storysunfolding]

my guess having owned a magna is that you have 10% ethanol gas now in your neighborhood. The fuel lines that came with the magnas will deteriorate when the ethanol goes through there. Did it look like marmalade in the float bowls? If so, replace your fuel lines, replace your inline fuel filter down by the fuel pump and you'll be good after you clean out the carbs.

Sorry guys, the magna's do come with a fuel filter, there is no petcock to speak of, though there is a valve down by the voltage regulator to turn off fuel flow before the pump to help winterize it