If I add a 4-1 pipe does carb need re-jetting????

I have a stock '79 KZ650 and I want to get a 4-1 pipe. Will the carbs need to be re-jetted? It still has the stock air box as well. I've had the bike about 1 year now and new to the KZ's so any help is appreciated

Andy

From what I've read, the answer is "maybe".

Depends on the specific pipes you get. Some mfr's claim that no rejetting is needed with stock airbox. But the best way to tell is to put them on, ride it for a bit, and look at the plugs to see if you are running lean.

I'm goin' with Skyman...which is 'maybe' but it is likely you'll opt for rejetting eventually...phrased another way, the scooter may run OK w/out rejetting but it may run the best w/rejetting...follow Skyman's advice, check your plugs.

I agree with the plug check also but..... IMO if a pipe say "no jetting required" then your getting NO benefits from it other than sound! A good pipe will scavage exhaust gasses out of the engine MUCH better than stock exhaust, thus the fuel flow at the carbs can't keep up with the new exhaust. So larger jets would be required. I love the sound of a 4/1 pipe but also like the power increase, my vintage (28 years old) Kerker was and still is one of the best pipes for these bikes.