aftermarket exhaust for 1979 cb 750

[stevewag]

I bought a 1979 cb 750 dohc some months past. It came with a period yoshimura full exhaust system 4 into one. It also had a stock, fairly old and dirty air filter. The thing runs but poorly and loves to hang when driven under load at 4000rpm. There are no air leaks at the rubber boots and idles and revs well when sitting in neutral. I believe it has a multitude of issues- charging, 1 of the float needles spring is seized, etc, but what I'm wondering first is should the air filter be upgraded because of the performance exhaust? I,m assuming the jetting is stock. Thanks,

steve

 

[coyote13]

I wouldn't assume anything about the jetting, but I'd say an upgrade to a K&N drop in filter would be warranted. There may be a slight increase in performance over stock, but the added benefit is a new, washable filter that isn't dirty, old, and crumbling. It's good cheap insurance, and a lot of guys prefer them over stock replacements since they are reusable.