my big bear will be running fine then acts like its loosing power and it will start hissing untill back fire then runs normal it is getting worse now but after it will back fire a few time it runs fine it sounds almost like the pipes blocked but i dont think thats the problem

 

need help please

 

This is mainly a boost so someone else will see your thread. My newbie guess is a piece of crud in the carburetor bowl that is getting sucked up against the main jet, making the mix too lean. When the vacuum drops, the crud drops and you run OK again. One can loosen the carb and remove the bowl without removing the carb from the quad. I saw a new carb on ebay for about $100 shipped.

I just bought a Big Bear 400 (2003) Tuesday. It set up for a few years. It will run OK under throttle, but won't idle. I have a friend coming over tomorrow to help me. I also got two Honda Recons - a quick carb clean and they run fine.

I hope you get a good answer soon, amigo.

 

thanks il try that