mufflers

I have a 1979 honda cb650 with some stock pipes im looking to replace. My question is whether or not i can do a 4-1 swap without re-jetting or any carb work, or is it necessary with a 4-2 to 4-1. As always input is appreciated. Thanks.

You will most likely need to rejet if you swap for a 4-1 system. Here's a spot that will give you a good starting point. http://motorcycles.wikia.com/wiki/Rejetting
Hope this helps and good luck.