My Big Bear is still not running right after I tried a carb from another bike that is running good, I took the head off removed the valves changed the seals and lapped valves. The exhuast valve was carboned up pretty bad as was the top of the piston. After cleaning the piston, changing the rings and lapping the valves it runs better but still has some poping back through the carb if I thumb the trottle 5 or 6 times in rapid succetion. I rode it up and down the street several time and it seem to perform well but I am concerned about the poping back through the carb while in the shop as mentioned above.

 

Is it poping back through the carb or poping through the exhaust?
In either case your pilot system is too lean. The air/fuel mixture screw (not the idle adjustment screw) should be at the bottom of your carb, generally turning it out will richen it.

 

Thanks Buckaroo, I figured it out while l was lying in bed. I went out to my shop and did exactly that. It is running great now. Thanks again.

 

Glad to hear it. Don't forget to go buy a windshield for your teeth. Getting the bugs off from smiling is a b_tch. And that bug removal stuff taste like crap... lol..

 

Looks like I smiled to soon the guy called me today and said that the bike was spittin and sputterin again. Do you think it could be an electrical problem? By the way it is popping back through the carb and the intake has a lot of gas in it when I pull the carb.