Do I have to Re-jet after putting a full exhaust???

Hey guys, I haven't seen any threads on this, but I'm buying a 4th gen exhaust for my 3rd gen because mainly, all slips ons are made for the 4th gen VFRs. To save some money, I was thinking to replace the 3rd gens crazy collector system for a 4th gen system and put a easy to find slip on and it will cost me less then $400. My question is, will I have to re-jet my bike? I'm also getting some carb work done here soon and I want to see if I should put the exhaust on first then do the carb work to fine tune it. If there are things I might run into by doing this, just let me know. Some advice would be great

 

Let the motor tell you what it wants. Either go on a dyno with gas analyzer or street riding for low mid range and 1/4 mile track for top end. Any surging at cruise means to lean with that throttle position, slow acceleration may be lean or to rich. Plug checks at track will tell. General condition of how plugs look for street riding will give a hint. Must use new plugs and proper shut down and reading at track will tell top end.

Your motor will tell you if you know how to listen/feel to what it is saying. Lots of variables to look at before just rejetting because of different exhaust. It may be as simple as raising the needles with stock jets. May be not.

 

Well, my riding style isn't much for racing, mostly cruising and commuting which short spurts up to 55 to get going. But others wise, thats as aggressive as I will get. So I guess I can drive the bike and feel how she runs. I might ask my mechanic to throw in my exhaust for me when I get all the parts together and also, he is doing my carb work for free because I'm giving him my CB700 nighthawk.....I guess that can wait. As for the spark plugs, dark sloppy crap means rich.....how do I spot a lean plug?

 

Lean plug ?? Porcelain white on center insulator.

Proppa colour in photo, a ruddy light tan.