This is a discussion on Big Bear 400 Carburetor rebuild question. within the Yamaha Big Bear/Bruin/Wolverine ATV Discussion forums, part of the Other Yamaha Forums category; I rebuilt the carb in my dads 01 bigbear last night. The thing had been sitting for a few years and was so full of ...
I rebuilt the carb in my dads 01 bigbear last night. The thing had been sitting for a few years and was so full of varnish I didnt notice that the two jets in the bottom of the carb were different sizes until I looked at my new parts. One has a smaller hole than the other. Which one goes where?
Well it will crank right up now. It seems to start cutting out at higher throttle. Also after you give it gas it seems to take a while to come back down to idle. This thing was pretty varnished up but i think I got all of the passages clean.
I just made the same mistake a few days ago on my Grizzly and I was getting the the same results. THe Big Bear's carb should be similar to the BSR42 in the Grizzly. It sounds like you've got your main and mid jets mixed up. The one with the largest hole goes in the big emulsion tube and it ends up being the tallest "post" sticking out from the carb body. The next size smaller jet goes in the shorter "post" right next to the main. The pilot jet should be a smaller diameter overall with a very small hole in it. If it starts right up and idle's OK but stumbles badly when you give it throttle, swap the main and mid jets around and see what happens.