2005 Yamaha PW80 Issues

Jul 5, 2016
Folks -

First time poster here, relatively new to 2 stroke machines in terms of repair.

I have a 2005 Yamaha PW80. I purchased it four years ago and it's been a good bike over all. My son rode it the first year, out grew it and my second son hasn't been interested so I've just been getting it started every year to make sure it's working.

This year, It started up with little trouble but for some reason it won't idle without throttle or choke. From here, I followed many of the maintenance directions. I replaced the gasoline, checked the spark plug, cleaned the air filter, and swapped the injected oil under the seat.

After all this, no difference. I tried adjusting the idle but that didn't seem to do anything. Finally, I decided to clean the carburetor. I followed some instructions online and got the bottom half off. I really expected it to be much dirtier in there. The only sign of use was a greenish hue where the gas and oil sat in the bottom on on the floats. I then turned the carburetor and removed what I believe are the intake valves? Two spring loaded valves on top. Again these look nearly brand new clean. I decided at this point to just put it back to together, which was a pain. The valves were hard to put back in and I noticed that the floats must be getting stuck because it took be several attempts to put the carb back together where gas didn't leak out of the overflow when testing it.

Now that it's back together the bike again starts really easy but now it's stuck in full throttle. Adjusting the idle does nothing and pulling back the throttle from the handle does nothing but a slight uptick in revs. I've obviously put the carburetor back improperly and the valves are like stuck open?

Can anyone give me a clue? Is there some general things to check when putting it back together? Any thoughts would be well appreciated.