Topic: CB550 carb or CB650 carb?

[Doggie]

Anyone install a CB650 carb on a CB550? Would it make a difference?
                                     Doggie

[Danno]

the 650 carb will work on the 550 but other than being a pain in the arse to get the jetting right there is no advantage
the 550 carbs can make a lot more horse power than they are asked to by the 550  if you want more power port it
line up the intake tracts and clean the flash out of the castings
 and add a 650 cam and tach gear or an after market webcam with longer duration not higher lift
loosening the exhaust and a foam air filter or k&n with 40 slows and 110 mains for a really loose exhaust but only to the edge of popping when you let off the throttle fast go a long way too

[Zodo]

I purchased a 77 Cb550k, not realizing that it had 1980ish Cb650 carbs on it...the the pd50b models. The bike also has pods, and runs really lean with the stock jets (35/90). The one advantage that you might get is an accelerator pump...it can result in snappier throttle response. I'm not entirely sure if it has a larger Venturi...so there may or may not be an advantage there. One thing to note is that the pd50 carbs have press in idle jets, which are a pain.

Once I get these carbs rebuilt and rejetted, they should do a decent job...but certainly not significantly better than the stock carbs.

[Doggie]

Thanks for the help. I think I will stick to the 550 carbs and change to a 650 cam.
                                     Doug

[Zodo]

Haha, I was almost hoping that you'd go for it so that I would have someone to commiserate with.