2001 Big Bear 400 misfiring/backfiring

[money_man]

My Big Bear 400 is having a problem. It will rev in neutral fine and 1st gear, but I barely give it fuel in 2nd and it starts backfiring and guys behind me said they can see black smoke. 3rd,4th, and 5th all do the same thing. I have to prematurely shift in order to get any speed which tops at about 40km/h and cant accelerate because it sounds like a popcorn machine banging and popping.

I tried to climb a hill and only got to the crest when a friend had to push me so the bike wouldnt flip backwards. In that instance even first gear wouldnt give me any power.

Any help would be appreciated, thanks.

[money_man]

forgot to mention the carb has been cleaned out and reassembled and this issue is still there.