Engine/Carb Parts Compatibility

[81gs1100]

You may want to reconsider this statement. the engine requires a proper A/F ratio.
drilling the pipe may or may not change the AFR.

No, the statment is correct, just interpeted wrong. I was saying a pipe change will not change the mixture. In order to change the carbs mixture you need to make adjustments to the carb. The pipe will just flow differently in turn the engine may need more fuel to match the more air it is flowing. Yes, you have to adjust the carb to get the proper air/fuel ratio afterwards.

The guy said modifing the pipe will change the carbs mixture... It will not, the carb will retain the same as it always has, but the engine may require more or less air/fuel ratio after a pipe change making the engine run lean or rich.

[rustybronco]

Changing the pipe may or may not affect the volume or air flowing through the carb.
needles and jets are capable of flowing only so much fuel. if you change the air flowing through the carb you will be changing the mixture (A/F).

to properly run, the engine still requires the same A/F. that does not change.

[tone]

Just to be devils advocate both rustybronco & 81gs1100 are wrong

Carbs rely on a vacum to suck the fuel/air mixture through them & into the engine, the scavenge effect created by the exhaust partly controls this ! drilling the exhaust will not change the carbs mixture settings as such but will effect the ability to scavenge effectively hence the probable need to rejet to suit

tone