2005 Yamaha PW 50 "wont build revs" Questions

build up carbon in the exhaust port, or the exit end of the muffler. They also need the original air filter and cover (dont know why, but they wont rev without it). I realize you may have checked some

...wont accelerate anymore.....could this be my cdi box going bad? It does sound like an ignition timing problem, but could also be a breathing issue, air flow in or exhaust flow out could be restricted ...

...wont start and when it does i have to hold the throttle open full and it will slowly build up to full rev? At the bottom of the carbs is a bolt.Its a 17mm I think.Turn the fuel off.Take the bolt off ...

...revs to the point where it then cuts out, then wont start for quite a while, then does the same thing. pulling what hair I have left out, hope you can help. I picked RS 125 as could not find my model ...

...wont tick over, it keeps cutting out unless you keep the revs up. I have cleaned the carb, replaced the plug and even the CDI. Still no joy! I Am running the right premix, the old plug looked fine - ...

wont start , engine turns over but dont seem to start check fuel pump fuse first..if good check fuel by pump taking off the line going to the carb and see if fuel comes out...use a gas can to catch ...

...wont try till warmer) any way the tank had been drained and no fuel....should i add some fuel stabelizer to the fuel? and should i add carb out she has been sitting for about a year and anything else ...