More often than not rejetting will be necessary but not always. as a general rule most bikes come lean from the manufacturer but this is not a 100% certainty.
Actually interesting to see so many riders wanting to rejet after switching exhausts when the bike was already lean before the new pipes. In other words the performance enhancing device actually hurts performance without the rejet.
Rejetting with the stock pipes would probably in most cases improve performance to about 90% of the rejet/pipe combo.
Cobra is a reputable outfit, and don't worry about the drill bit, there is a sealed tube that hides the air/fuel mixture ajusting screw, the bit is only to remove the "sealer" from this tube allowing access to the screw. This is on the outside of the carb, you won't be drilling inside the carb.
Do you need to rejet ? after installing the new pipe is the bike running better or not ? Try removing the air filter to see if it improves ( removing the air filter will allow more air therefore leaning out the mixture even more, I doubt this will improve anything ) then try partially covering the air intake ( reducing air will make the mixture richer, if this makes it run better then you need to rejet).
Actually interesting to see so many riders wanting to rejet after switching exhausts when the bike was already lean before the new pipes. In other words the performance enhancing device actually hurts performance without the rejet.
Rejetting with the stock pipes would probably in most cases improve performance to about 90% of the rejet/pipe combo.
Cobra is a reputable outfit, and don't worry about the drill bit, there is a sealed tube that hides the air/fuel mixture ajusting screw, the bit is only to remove the "sealer" from this tube allowing access to the screw. This is on the outside of the carb, you won't be drilling inside the carb.
Do you need to rejet ? after installing the new pipe is the bike running better or not ? Try removing the air filter to see if it improves ( removing the air filter will allow more air therefore leaning out the mixture even more, I doubt this will improve anything ) then try partially covering the air intake ( reducing air will make the mixture richer, if this makes it run better then you need to rejet).
