[jjr]

I am installing MAC 4 into 2 exhaust on my 81 GS650G. Do I need to do anything to the carb or ? or do I just bolt it on and go?

Thanks in advance

 

[Clint]

For optimum power gains you'd usually rejet for more fuel. It's not always necessary, but your mixture will likely get a bit leaner.

 

[advr4]

is it a full system or just a slip-on? if its a full system, you should re-jet your carbs to avoid running too lean.