B4 flat from 4k to 6k?

[hickman71]

I just bought a '92 B4 and it is flat from 4k to 6k. I'm assuming that this is butterfly not opening or a clogged jet?

[interfuse]

Probably a jetting problem. Pretty common. Figure out if it's rich or lean. If your carbs are in pretty good shape it's probably lean (gets better as the bike warms up). If you needle jets are worn then it's rich (gets worse as the bike warms up). If it's lean you could try adding more oil to your airfilter. If it's rich try adding more air (less oil on filter or drilling holes in your airbox). However that might cause problems elsewhere... fun.

We have such drastic weather here -- I'm always messing with something.