I left my bike set up for a while, took it out to go to the deer camp and it ran really rough. So when I got home I took the carb off and cleaned it up, found a little build up in the bottom was all. It seems all the fartin and backfiring is in the low RPM's, its poping back in the carb. when I give it gas. I am going to get a plug today, I don't know what else it could be, it only has 500 miles on it, (2004 model). any help would be appreciated.

 

Sounds like maybe a dirt dobber has plugged your vent line from the carb. Did you drain all of the old gas and use new? The only other thing it could be is a plugged pilot circuit in the carb. That would cause the lower rpm problems the most.

 

I will check the vent, I pulled all the jets and sprayed carb. cleaner in them, I am more than sure they are clear. I just payed the thing off, so they must of zapped it! No extended warranty! If it was a valve or something it would do it all the time huh? Once you get the RPM's up without it dieing, it screams. Yea, I did drain the old gas and put new in with some cleaner too, did that then ran it for a while. No help though, sounds like a trip to the shop, that pisses me off!

 

The pilot jet needs to be unscrewed, and cleaned. It cant be cleaned properly if its still in the carb.
If the center hole is plugged and wont clear out...then get a new pilot jet.
Warentee wouldnt have covered this.

 

I had a Yamaha Big Bear one time that caused me all kinds of grief. It had a piece of trash that would bobble around and plug the pilot circuit from time to time. It finally got lodged it the pilot fuel passage. Took it to the shop and they tried to sale me a new carb., I said I would fix it. Found a used carb, installed a fuel filter and had the fuel problems fixed. You might can pull the carb, disassemble it and let the body soak in some real carb cleaner for a while. After that blow the pilot ports out with some good air pressure. The mixture screw that hondabuster speaks of is just part of the pilot circuit. The CVK type carbs have some wild pilot circuits.

 

Update on problem! I took carb. back off (4th time), took all the parts off of it I could (jets, diaphram on top), I drilled out the mixture screw cover and removed the adustment screw, soaked it for a while in carb cleaner. I then sprayed it down through all ports that I could, blew it down with air, put it back together. Yepper, it ran, it won't idle yet, but I think that is an adjustment thing I hope, it got late on me, so I will return to it today. One thing though, when I took the carb off, the intake all the way back to the air filter housing was full of gas, I think it was leaking from the vaccum hose that goes to the fuel valve, does that mean the valve is bad? I will see this afternoon if it did it again, when I had it apart I verified that the float was working right.

 

The mixture screw should be set at 1 1/4 - 1 3/4 turns out on a stock Vinson. Make sure your fuel valve is set to ON and not PRIME. Will it idle if you choke it? Check your oil level and make sure its not saturated with fuel if you left the valve in the prime position. Let us know when you get it fixed.

 

The valve was in the reserve position, Thanks for the reminder about the oil, I had thought about it when I found it, but went on the work on carb. When it started and ran I got excited and forgot completely about it.

 

If you were running it on reserve you may have picked up some trash from the bottom of the tank and started this whole fiasco. Good luck.....